Taner Yildirim 's Resume CV Vitae

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CURRICULUM VITAE

TANER YILDIRIM
NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
Phone: (301) 975-6228 Fax: (301) 921-9847 Email:taner@nist.gov

RESEARCH OBJECTIVES
PROFESSIONAL EXPERIENCE AND EDUCATION
AWARDS AND RECENT SCIENTIFIC ACTIVITIES
MAJOR ACCOMPLISHMENTS
INVITED TALKS AT WORKSHOPS AND CONFERENCES
AREAS OF EXPERTISE
REFERENCES AND RECENT IMPORTANT COLLABORATORS
LIST OF PUBLICATIONS

RESEARCH OBJECTIVES

My research objectives include: (1) conducting research to solve outstanding problems in theoretical and experimental solid state physics, (2) developing theories to improve our understanding of structural, magnetic, and transport properties of novel materials, and (3) combining this understanding with synthesis and first-principles computational techniques to discover new advanced engineered materials with desired properties for practical applications. Systems of interest include order/disorder phenomena and lattice dynamics in molecular solids such as the fullerenes and cubane, spin structure and quantum dynamics in frustrated magnetic systems such as the Kagome lattice and cuprates, novel superconductors such as doped fullerenes and magnesium diboride, and mechanical and magnetic properties in nanomaterials such as nanotubes and molecular magnets.

PROFESSIONAL EXPERIENCE

Staff Physicist: 1997-present
NIST Center for Neutron Research, Gaithersburg, MD 20899

Research Associate: 1994-1997
University of Maryland, College Park, Maryland.

EDUCATION

PhD 1990-1994
Department of Physics, University of Pennsylvania, Philadelphia, Pennsylvania.
Thesis: Theoretical and experimental study of solid C1#1 and its Na-doped derivatives and also quantum magnetism and magnetic structures of lamellar perovskite antiferromagnets.
Thesis Advisor : Prof. A. B. Harris and Prof. J. E. Fischer
MSc 1988-1990
Department of Physics, Middle East Technical University, Ankara, Turkey.
Thesis: Electron-phonon interactions in low dimensionally confined quantum well type semiconductors.
Thesis Advisor: Prof. Atilla Ercelebi
BS 1985-1988
Department of Physics, Middle East Technical University, Ankara, Turkey.

PROFESSIONAL MEMBERSHIPS

Member, American Physical Society (APS).
1994 Complimentary membership, Materials Research Society (MRS).
Member, Electrochemical Society (ECS).
Member, American Crystallographic Association (ACA).

AWARDS

2001-2003 National Science Foundation Grant No: INT 01-15021: Experimental and Theoretical Investigation of Nanoscale Materials and Devices Based on Carbon Nanotubes, a collaborative research project between University of Pennsylvania, NIST, and Bilkent University, Ankara, Turkey.

1997-2000 National Science Foundation Grant No: INT 97-31014: International Cooperative Research Project on Cubane between University of Maryland, NIST, and Bilkent University, Ankara, Turkey.

1993 Materials Research Society Award: In recognition of outstanding performance in the conduct of research

RECENT SCIENTIFIC ACTIVITIES

Organizer, focussed sessions on Fullerenes and Nanotubes for the Division of Materials Physics, APS March Meeting, 2001.

PUBLICATIONS

Over 65 peer-reviewed papers in theoretical and experimental condensed matter and materials physics
Over 700 citations
Over 40 invited presentations at conferences, universities, and research centers in the US and Europe.

MAJOR ACCOMPLISHMENTS

The recent surprise discovery of superconductivity in magnesium diboride (MgB2#2) at 39 K has led researchers to wonder whether the origin of the high T3#3 is an electron-phonon or other exotic mechanism? By combining first-principles calculations and inelastic neutron scattering measurements of the phonons in MgB2#2, we offered the first direct answer to this fundamental question. The calculations reveal that the in-plane boron phonons (with E4#4 symmetry) near the zone-center are very anharmonic. Moreover these modes strongly couple to the partially occupied planar B 5#5 electronic bands near the Fermi level. We showed that this giant anharmonicity and non-linear electron-phonon coupling is the key to quantitatively explaining not only the observed high T3#3 and boron isotope effect in MgB2#2 but also the pressure dependence of the T3#3. The excellent agreement between theory and our inelastic neutron scattering measurements of the phonon density of states gives confidence that the calculations provide a sound description of the physical properties of the system. This work (Phys. Rev. Lett. 87, 37001 (2001)) has revived a great deal of interest within the physics community as evidenced by recent articles in Physical Review Focus (July 2001), in September 2001 issue of Materials Today. I have also been invited to present this work at the upcoming APS March Meeting, the Workshop on Spectroscopies of Novel Superconductors (SNS2001) held in Chicago, the International Symposium on Superstripes held in Rome, and Argonne National Lab. More information can be found at http://www.ncnr.nist.gov/staff/taner/mgb2. This website has been visited over 2500 times, another indication of the impact of our work in this area.

Carbon nanotubes, originally discovered as a by-product of fullerenes synthesis, are one of the most promising nanomaterials. We have used first principles calculations to elucidate details of the electronic and chemical properties of these systems. Our first work in this area resulted in the prediction that by applying pressure, carbon nanotubes can be covalently joined to form one and two-dimensional networks of interlinked nanotubes. Several months after our prediction was published, the results were independently confirmed experimentally (see PRL 86,3056 and PRB 64,153401). The second major accomplishment in nanotube research was the discovery that the band gap of an insulating nanotube can be engineered by elliptical distortion. This work has significant implications for designing electronic nanodevices based on nanotubes. Finally, we have very recently shown (see PRL 87,116802) that the chemical reactivity of nanotubes can be tuned by elliptical deformation, which may provide a way to attach various atoms such as H and metals to a specific location on a nanotube. I have been invited to present this research at a workshop on Computational Nanoscience for Industrial Applications in Houston and at the ASTATPHYS-2001 (Nanoscience Meeting) held in Cancun, Mexico (July, 2001). In addition, an article about our research appeared in the November issue of Materials Today. Further details of this research can be found at http://www.ncnr.nist.gov/staff/taner/nanotube.

The cubane molecule (C6#6H6#6) is aesthetically appealing due to the highly symmetric cubic shape. Moreover it is the most highly strained, kinetically stable ring system available in quantity, and therefore offers promise in many diverse and interesting practical applications as explosives, high-refractive index lenses, specialty polymers, and fuel additives. While cubane was first synthesized and the room temperature crystal structure was determined in the early 1960's, the high temperature, orientationally disordered structure remained unknown due to experimental difficulties arising from the high vapor pressure and the associated problem of recrystallization. In 1997, we surmounted these challenges and using X-ray and neutron scattering along with various theoretical models, characterized the disordered phase of solid cubane (see Phys. Rev. Lett. 78, 4938, 1997). This work received enormous interest as evidenced by articles in The New York Times (July 15,1997), Science News (52, p. 34, 1997), and Physics Today News Updates (p. 9 August 1997). I have been invited to the University of North Carolina, Chapel Hill, to Ruhr University in Bochum, Germany, and to the European Materials Research Society Meeting in Strasbourg, France to present this work.

The discovery of a simple method of making large quantities of fullerenes initiated a great deal of research into the properties of fullerenes and compounds based on fullerenes. Several phases of C1#1 with alkali metals such as K, Rb, and Cs were reported. However, due to reactivity of smaller alkali metals and several technical difficulties, the phase diagram of C1#1 with Na and Li were not know. In 1992 we developed a new synthesis technique using copper tubing and alkali-metal azide to remedy these difficulties and reported the first solid-state synthesis and x-ray characterization of the saturated phase of the Na-C1#1 system: intercalation of heteroclusters into solid C1#1. (See T.Yildirim et al. Nature, 350, 568 (1992)). This work suggested that by using smaller alkali metals (i.e. Li), it would be possible to intercalate even more atoms into the host lattice, a finding of great interest for Li batteries. I was awarded the Materials Research Society Award in recognition of outstanding performance in the conduct of research for this work and I have been invited to give several presentations based on this research (see the list of invited talks). This work has been cited nearly 100 times, a clear indication of its impact.

C1#1 molecules adopt several different orientations in the solid state depending on various factors including temperature and intercalated species. In 1993, we combined synthesis and characterization of new C1#1 based materials with theoretical calculations to provide a unified view of orientational ordering of C1#1 in C1#1-based solids (see T.Yildirim et al. Phys. Rev. Lett. 71, 1383 (1993)). This work resulted in the widespread realization of the importance of molecular orientational order/disorder phenomena on properties such as superconductivity. I have been received invitations to speak on this subject at many research centers and conferences including the American Physical Society March Meeting in 1994, an international workshop on fullerenes held in Austria 1994. This work has been cited more than 60 times.

The discovery of superconductivity in A7#7C1#1 compounds where A is K, Rb, or Cs sparked a great deal of interest in the condensed matter physics community. It was quickly realized that the superconducting transition temperature depends strongly on the lattice constant which could be easily controlled by changing the alkali metal or by applying external pressure. This dependence was attributed to the changing density of electronic states at the Fermi level. To explore this idea further, one would like to adjust the carrier concentration in these systems. Unfortunately this was fixed at three electrons per C1#1 molecule due the narrow solubility range in the phase diagram of these compounds. We overcome this problem by synthesizing two novel families of fullerides; Na2#2Cs8#8C1#1 and M9#9Ba8#8C1#1, thereby allowing the first studies of the correlation between the superconducting transition temperature and the carrier concentration. (See T. Yildirim et al Phys. Rev. Lett. 77, 167 (1996)). This work clearly demonstrated that the mechanism of superconductivity in these systems is unique and quite different than that in the high T3#3 cuprates. I have made invited presentations on this subject at the Euroconference on novel superconductor materials, in Pisa, Italy (Jan. 1996), at the Electrochemical Society Meeting in Los Angeles (May 1996) and at many universities and research centers.

A longstanding problem which has attracted much interest recently concerns the mechanism whereby spin-orbit interactions give rise to magnetic anisotropy in magnetic insulators. Until recently the discussions of the origins of anisotropy found in cuprates were confined to the orthorhombic structure (i.e. La2#2CuO10#10). However, more recently a family of copper oxide materials of similar structure, but which are actually tetragonal, have been studied and found to have roughly the same out-of-plane anisotropy as La2#2CuO10#10. The earlier studied did not predict any anisotropy in the tetragonal limit. Explaining this discrepancy was the main purpose of our work. We developed a theory which for the first time corrects, extends, and clarifies results concerning the spin Hamiltonian used to describe the ground manifold of Hubbard models for magnetic insulators in the presence of spin-orbit interactions. (See T. Yildirim et al, Phys. Rev. Lett. 73, 2919 (1994)). The biggest impact of this work is the demonstration that almost all previous work which invoked the orthorhombic distortion to explain the observed anisotropy in cuprates (causing the spins to lie in the Cu-O plane) are wrong. Our theory clearly shows that this anisotropy is due to spin-orbit and Coulomb exchange interactions and independent of distortion. I have been invited to many labs, including NEC and IBM, to give seminars on this work.

Magnetic interactions in the tetragonal copper oxide systems (which exhibit high temperature superconductivity after doping) have been extensively studied with the hope that a step towards the understanding of the high-temperature superconductivity would be to understand the simpler undoped systems such as Sr2#2CuO2#2Cl2#2 and R2#2CuO10#10 (R=Pr, Nd, etc). Despite the fact that all cuprates have a very similar structures, they exhibit very different three dimensional (3D) spin ordering. Hence the nature of magnetic interactions which determine the 3D magnetic spin structure was not known. We show that the spin Hamiltonian of the tetragonal lamellar antiferromagnets contains several novel anisotropies (See T. Yildirim et al, Phys. Rev. Lett. 72, 3710 (1994)). Using these anisotropic interactions, we developed a theory that successfully explains for the first time the spin structures of many cuprates. This work has been presented at many labs including NEC and IBM.

INVITED TALKS AT WORKSHOPS, CONFERENCES, AND UNIVERSITIES

The theory of superconductivity in MgB2#2, at the first international workshop on Superconductivity in Magnesium Diboride and Related Materials, to be held in Genoa, Italy (on June 17-19, 2002).

First-Principles Zone-Center Theory of 40 K BCS Superconductivity in MgB2#2, at "American Physical Society Meeting", Indianapolis, IN (March 2002).

A Simple BCS Theory of 40 K Superconductivity in MgB2#2, at International Symposium on "Artificial and Natural Nanostructures - Superstripes", Rome, Italy (December 2001).

Experimental and Theoretical Investigation of Nanoscale Materials and Devices Based on Carbon Nanotubes, at the Applied Statistical Physics Molecular Engineering Conference, Cancun, Mexico (July 23-27, 2001 ).

Giant Anharmonicity and Non-Linear Electron-Phonon Coupling in 40 K Superconductor MgB2#2, at the Spectroscopies of Novel Superconductors (SNS), Chicago (May 13-17,2001)

New High T3#3 Boron Superconductor, at "Materials Science Division Seminar, Argonne National Laboratory", (host: Dr. James. D. Jorgensen), Argonne, Illinois (April 2001).

Combined Neutron Scattering and First-Principles Investigation of New High T3#3 Boron Superconductor, at "Condensed Matter Seminar, Physics Department, University of Illinois at Chicago", (host: Prof. Inder Baltra), Chicago, Illinois (April 2001).

First-principles and Neutron Scattering Study of Proton Conductors, at the 10th international conference on Solid State Protonic Conductors, Montpellier, France (Sept. 2000).

Combined Neutron Scattering and First-Principles Study of Novel Materials, at the American Crystallographic Association, St. Paul, MN, (July, 2000).

Structure and Dynamics from First-Principles, at the MSI Workshop on Applications of Quantum Mechanics in the Catalysis, Chemicals, and Electronic Industries, (Chicago, May 2000).

Application of neutron scattering methods to the study of protonic conductors, at Sacley, Paris, France (April 2000, Host: L. T. Lee).

High-Spin Magnetic Molecules: Molecular Approach to Nanomagnetism, at the Harrisfest Symposium at the University of Pennsylvania, Philadelphia, PA (March, 2000).

Combined neutron scattering and first-principles studies of novel solids, at the international conference "Neutrons and Numerical Methods", Institut Laue-Langevin, Grenoble, France (December 1999, Host: Mark R. Johnson).

First Principles Calculations and Neutron Scattering, lecture at the NCNR Workshop on Cold Neutron Spectroscopy, NIST, Gaithersburg (August, 1999).

Carbon Based Molecular Clusters: Cubane and Fullerenes, at the international meeting NATO ASI on the Quantum Mesoscopic Phenomena, Ankara/Antalya, Turkey (June 1999, Host: Prof. Igor O. Kulic).

First Principles Study of Structure and Dynamics of Solid Cubane , at the "5th Statistical Physics Meeting", Istanbul Technical University, Turkey (July 1998).

Unusual Structure, Phase Transition, and Dynamics of Solid Cubane, at Naval Research Laboratory (NRL), Washington DC (Host: Dr. John Mintmire, June 1998).

Fullerene Based Superconductors, at "the 193th Electrochemical Society Meeting", San Diago, California (May 1998).

Neutron and X-ray Study of Structure and Dynamics of Solid Cubane, at Condensed Matter Seminar, University of North Carolina, Chapel Hill, NC (Host: Prof. Otto Zhou, Oct.1997).

Unusual Structure, Phase Transition, and Dynamics of Solid Cubane, at Condensed Matter Seminar, University of Bochum, Germany (July 1997).

Theory of Inelastic Neutron Scattering, at NCNR Workshop on Cold Neutron Spectroscopy, NIST, Gaithersburg (August, 1997).

Ordering due to Disorder in Frustrated Quantum Magnetic Systems, at the "4th Statistical Physics Meeting", Istanbul Technical University, Turkey (July 1997).

First Principles Approach to Intermolecular Interactions in Solid C1#1, at Condensed Matter Seminar at the University of Antwerpen, Belgium ( July 1997, Host: Prof. K. H. Michel).

First Principles Study of Structure and Dynamics of Solid Cubane, at "European Materials Research Society Meeting", Strasbourg, France (June 1997).

Synthesis and Properties of Mixed Alkali-Alkaline Earth Fullerides, at Condensed Matter Seminar at the INST CHARLES SADRON, Strasbourg, France (June 1997).

Variable Valence and Superconductivity in Fullerides, at "American Physical Society Meeting", Kansas City, MO (March 1997).

T3#3 vs. carrier concentration in cubic fulleride superconductors, at "the 189th Electrochemical Society Meeting", Los Angeles, California (May 1996).

Superconductivity in doped-fullerene, at "the colloquium held in Physics Department, Ohio University", Athens, Ohio (April 1996).

T3#3 vs. carrier concentration in cubic fulleride superconductors, at "Workshop on New Perspectives in Unconventional Superconducting Materials", Pisa, Italy (January 1996).

Three-dimensional Ordering in bct Antiferromagnets due to Quantum Disorder, at Condensed Matter Seminar at the University of Pennsylvania, Philadelphia (April 1995).

Intermolecular Potentials and Theory for the Observation of Librons in Solid C1#1, at "International Winterschool on Electronic Properties of Novel Materials", Kirchberg, AUSTRIA (March 1994).

Orientational Ordering of C1#1 in Na-Doped Systems, at "American Physical Society Meeting", Pittsburgh, Pennsylvania (March 1994).

Anisotropic Spin Hamiltonian due to Spin-Orbit and Coulomb Exchange Interactions and Spin Structure of Tetragonal Lamellar Copper Oxides, at "IBM Thomas J. Watson Research Center", (host: Dr. David DiVincenzo), Yorktown Heights, New York (February 25,1994).

Spin Structure of Tetragonal Lamellar Copper Oxides, at "NEC Research Institute ", (host: Dr. Ned Wingreen), Princeton, New Jersey (February, 1994).

Orientational Phase Transition in Na8#8C1#1, at "AT&T Bell Laboratories", (host: Dr. Art Ramirez), Murray Hill, New Jersey (February 1994).

Structure and Dynamics of Na8#8C1#1, at "Materials Science Division Seminar, Argonne National Laboratory", (host: Dr. James. D. Jorgensen), Argonne, Illinois (May 1994).

Orientational Order/Disorder in Na8#8C1#1, at "International Winterschool on Electronic Properties of Novel Materials", Kirchberg, AUSTRIA (March 1994).

Neutron and X-ray Study of Na-doped C1#1 compounds at "NIST Center for Neutron Research, NIST", (host: Dr. Dan Neumann), Gaithersburg, Maryland (March, 1994).

Phase Diagram of Na-doped C1#1, at "IBM Thomas J. Watson Research Center", (host: Dr. David DiVincenzo), Yorktown Heights, New York (February 22,1994).

Na-doped C1#1 compounds at "Brookhaven National Laboratory", (host: Dr. John Axe), Upton, New York (February, 1994).

Intercalation of sodium heterocluster into the C1#1 lattice, at the Materials Research Society Meeting, Boston (November 1993).

Theory of Orientational Phase Transition in Na8#8C1#1, at the University of Montpellier, France (June, 1993, Host: Prof. B. Patrick).

QUALIFICATIONS

Skills in Theoretical Condensed Matter and Materials Physics

Qualification: Theory of Crystal Structure and Dynamics
Specialized in lattice dynamics and crystal structure calculations based on phenomenological potential models and density functional theory. Extensive experience in first principle calculations of the structures of molecules such as C1#1 and cubane using Gaussian 94 and Castep packages. Demonstrated experience in ab initio calculations of the intermolecular interactions, crystal structure, and other properties such as inelastic neutron scattering spectrum of molecular solids.
Evidence: More than ten publications in prestigious journals including Physical Review Letters and Physical Review B. These works are cited extensively by others, indicating the importance of the work. For instance, ``Lattice dynamics of solid C1#1", ``Multipole approach to orientational interactions in solid C1#1" , and ``Orientational phases for M7#7C1#1" have been cited 53, 27, and 30 times respectively. I also gave many invited talks on this work (see the list of ``invited talks").
Qualification: Theory of Magnetism of Novel Materials
Specialized in the derivation of macroscopic spin Hamiltonians for magnetic materials starting from a multi-band Hubbard model in the presence of spin-orbit and Coulomb exchange interactions. Tools are degenerate perturbation theory, exact numerical diagonalization on small clusters, etc. Also demonstrated experience in calculation of spin structures, inelastic neutron scattering intensity calculations, crystalline electric field (CEF) calculations for rare-earth cuprates, and many other systems.
Evidence: Two Physical Review Letters[52],[53] and two Physical Review B [38],[48] articles. The Physical Review Letters ([52] and [53]) have been cited 16 and 24 times respectively.
Qualification: Frustrated Quantum Magnetic Systems
Specialized in the calculation of the effects of quantum fluctuations on the ground state properties of frustrated magnetic systems such as BCT, FCC and Kagome antiferromagnets. Tools are 1/S expansion, interacting and non-interacting spin waves, perturbation theory and exact numerical diagonalization.
Evidence: Three recent publications ``Three-dimensional ordering in bct antiferromagnets due to quantum disorder", ``Frustration and Quantum Fluctuations in Heisenberg FCC Antiferromagnets" , and ``Ordering due to Disorder in Frustrated Quantum Magnetic Systems". The later article is a review of the current status of this field and it was presented as an invited talk at an international conference.
Qualification: General Computer Knowledge
Extensive computer programming, mostly using Fortran, C++, Tcl and Tk. Have a good knowledge of UNIX, DOS, etc.
Evidence: Several codes that I have written during the last four years. Some of these are as follows: (1) tantreat: a code to visualize and to analyze quasielastic data from TOF instrument for each detector simultaneously; (2) tancef: a code to calculate the inelastic neutron spectrum of the crystalline electric field (CEF) levels of rare-earths such as Nd and Sm for arbitrary site symmetry with and without J-coupling effects; (3) tancastep a Tc-Tkl script program to perform first-principles lattice dynamics calculations and inelastic neutron spectrum of the zone center phonons of any solid. This script code uses first-principles CASTEP code to calculate the total energies and forces on the ions. (4) tandmat a code to calculate dynamical matrix and phonon dispersion curves, DOS, and inelastic neutron spectrum for molecular solids using phenomenological intermolecular potential.

Skills in Experimental Condensed Matter and Materials Physics

Qualification: Neutron and X-ray Scattering
Specialized in various neutron scattering techniques such as powder and single crystal diffraction on both magnetic and non-magnetic samples, time-of flight measurements (TOF), quasielastic and inelastic neutron scattering (both coherent and incoherent). Very extensive experience in X-ray powder diffraction using both the INEL-diffractometer and the NSLS synchrotron X-ray at Brookhaven National Laboratory. Specialized in ab initio structure characterization from both X-ray and neutron data using Rietveld refinement (GSAS).
Evidence: More than ten publications in prestigious journals. These works are cited extensively by others. For instance, `` Orientational phase transition in Na8#8C1#1 ( 11#11) ", ``T3#3 vs. carrier concentration in cubic Fulleride Superconductors", and "Fulleride Superconductors and Orientational Order: T3#3 vs. Lattice Constant in Na2#2Rb8#8Cs12#12C1#1," have been cited 62, 49, and 45 times respectively. As also evident from the list of the invited talks, I have been recognized by a large number of scientists in this field.
Qualification: Solid State Synthesis
Specialized in solid state synthesis including intercalation compounds and high temperature ceramics as well as single crystal growing (e.g. Sr2#2CuCl2#2O2#2). Eight years of experience in glove box and vacuum line manipulations of air-sensitive materials.
Evidence: More than six publications. For instance, "``Intercalation of sodium heteroclusters into the C1#1 lattice", and "Fulleride Superconductors and Orientational Order: T3#3 vs. Lattice Constant in Na2#2Rb8#8Cs12#12C1#1," have been cited 92 and 45 times respectively.
Qualification: General Experimental Knowledge
Good knowledge of thermal analysis (such as DSC, MDSC), ESR, magic angle spinning (MAS), solid state NMR, and Raman scattering on powder samples.
Evidence: My invited visits to the labs of the world experts including Prof. H. Kuzmany (Raman expert), Austria, Prof. B. Patrick (NMR expert), France, are the most clear evidence. Publications ``ESR evidence for phonon-mediated resistivity in alkali fullerides", ``Raman Spectra of Sodium Saturated doped Na8#8C1#1 (x=9.2 and 9.8)", and ``C13#13 and Na14#14 NMR Studies of Na2#2C1#1 and Na15#15C1#1 fullerides" are the additional evidence for my general knowledge of ESR, Raman, and NMR techniques.

EXPERIENCE

1988 - 1990: Instructor, Department of Physics, METU, Ankara, Turkey
1990 - 1992: Teaching Assistant, Department of Physics, University of Pennsylvania
1992 - 1994: Research Assistant, Department of Physics, University of Pennsylvania
1994 - Present: Staff Physicist at the Univ. of Maryland and NIST

REFERENCES

Prof. A. B. Harris, Physics Department, University of Pennsylvani, PA 19104
Email: harris@physics.upenn.edu

Prof. J. Fischer, LRSM, University of Pennsylvania, PA 19104
Email: fischer@sol1.lrsm.upenn.edu, Phone: (215) 898-6924

Dr. Dan Neumann, NIST Center for Neutron Research, NIST, Gaithersburg, MD 20877
Email: dan.neumann@nist.gov, Phone: (301) 975-5252

Dr. Ronald L. Cappelletti, NIST Center for Neutron Research, NIST, Gaithersburg, MD 20877
Email: ronald.cappelletti@nist.gov, Phone: (301) 975-6221

Dr. Jeffrey Lynn, NIST Center for Neutron Research, NIST, Gaithersburg, MD 20877
Email: jeffrey.lynn@nist.gov, Phone: (301) 975-6246

Prof. Amnon Aharony, Physics Department, Tel Aviv University, Israel
Email: aharony@ccsg.tau.ac.il, Phone: (972)-3-6408558

IMPORTANT COLLABORATORS DURING THE PAST FIVE YEARS

Prof. J. E. Fischer and Prof. A. B. Harris (Univ. of Pennsylvania)
Prof. Amnon Aharony and Prof. O.Entin-Wohlman (Tel Aviv University, Israel)
Prof. P. W. Stephens (SUNY-Stony Brook&Brookhaven National Laboratory)
Dr. Jim Jorgensen (Argonne National Laboratory)
Dr. Dan Neumann and Dr. Jeff Lynn (NIST)
Prof. E.F.Shender (Univ. of CA, Berkeley)
Prof. H. Kuzmany (University of Vienna)
Dr. P. Barnier and Dr. F. Rachdi (GDPC Montpellier, France)

PERSONAL

Born: 02/ 05/ 1968 - Kars, Turkey
Nationality: Turkish, permanent resident in the USA based on E11 category "Alien of Extraordinary Ability in Sciences".
Married: Emel Yildirim (Turkish, permanent resident in the USA)

PUBLICATIONS IN SCHOLARLY JOURNALS
WITH INTERNATIONAL CIRCULATION

[1]

`` Magnesium diboride: The surprising superconductor of 2001",

T. Yildirim, an insight feature to appear in April issue of Materials Today (Elseview Science) (in press, 2002).

[2]

`` Temperature and field dependence of magnetic excitations in molecular magnet Mn16#16: A neutron scattering study",

T. Yildirim and S. H. Lee, Phys. Rev. B (submitted, 2002).

[3]

`` Magnetic excitations in the 3D Molecular-Based Magnets Mn(N(CN)2#2)2#2 ",

H. N. Bordallo, T. Yildirim, S. H. Lee, L. C. Chapon, J. L. Manson, J. C. Cook, and J. R. D. Copley, Phys. Rev. Lett. (submitted, 2002).

[4]

`` A Simple Theory of 40 K Superconductivity in MgB2#2; First-principles Calculations of T3#3, its dependence on boron mass and pressure",

T. Yildirim and O. Gulseren, J. Phys. and Chem. (in press, 2002).

[5]

`` Phonons and Elasticity of MgB2#2 at High Pressures; Implications to its Superconductivity",

O. Gulseren and T. Yildirim, Phys. Rev. B (submitted, 2001).

[6]

`` Novel Effects of Hydrogen Adsorption on Single Wall Carbon Nanotubes; metallic hydrogen-decorated square SWNTs",

O. Gulseren, T. Yildirim, and C. Ciraci, Phys. Rev. Lett. (submitted, 2001).

[7]

`` A systematic ab-initio study of curvature effects in carbon nanotubes",

O. Gulseren, T. Yildirim, and C. Ciraci, Phys. Rev. B (in press, 2002).

[8]

`` Tunable Adsorption on Carbon Nanotubes",

O. Gulseren, T. Yildirim, and S. Ciraci, Phys. Rev. Lett. 87, 116802 (2001).

[9]

`` Giant Anharmonicity and Non-linear Electron-Phonon Coupling in MgB2#2 ",

T. Yildirim et al., Phys. Rev. Lett. 87, 37001 (2001).

[10]

`` Exo-hydrogenated Single Wall Carbon Nanotubes",

T. Yildirim, O. Gulseren, and S. Ciraci, Phys. Rev. B 64, 075404 (2001).

[11]

`` Combined Neutron Scattering and Firs-Principles Study of Solid State Protonic Conductors",

T. Yildirim, B. Reisner, T. J. Udovic, and D. A. Neumann, Solid State Ionics 145, 429 (2001).

[12]

`` Scientific Reviews: The Dynamics of Solid Cubane",

T. Yildirim, P. M. Gehring, and D. A. Neumann, Neutron News, Vol. 12, No. 2, Page 34 (2001).

[13]

`` Vibrational mode analysis of isomorphous hydrogen-bonded guanidinium sulfates with inelastic neutron scattering and density-functional theory",

A. M. Pivovar, M. D. Ward, T. Yildirim, and D. A. Neumann, J. Chem. Phys. 115, 1909 (2001).

[14]

`` Superconductivity in the polymeric phase of Na2#2CsC1#1",

J. E. Schirber, B. Morosin, G. H. Kwei, T. Yildirim, J. E. Fischer, and J. D. Jorgenson, Physica C 353, 207 (2001).

[15]

`` Variable and Reversible Quantum Structures on a Single Carbon Nanotube",

C. Kilic, and S. Ciraci, O. Gulseren, T. Yildirim, Phys. Rev. B 62, R16345 (2000).

[16]

``Pressure Induced Interlinking of Carbon Nanotubes",

T. Yildirim, O. Gulseren, C. Kilic, and S. Ciraci, Phys. Rev. B 62, 12648 (2000).

[17]

``Structure and Dynamics from Combined Neutron Scattering and First-Principles Studies",

T. Yildirim, Chem. Phys. 261, 205 (2000).

[18]

``First-Principles Investigation of Structural and Electronic Properties of Solid Cubane and its Doped Derivatives",

T. Yildirim, S. Ciraci, and A. Buldum, Phys. Rev. B 62, 7625 (2000).

[19]

``Quantum Rotation of Hydrogen in Single-Wall Carbon Nanotubes",

C. M. Brown, T. Yildirim, D. A. Neumann, M. H. Heben, T. Gennett, A.C. Dillon, J.L. Alleman, and J.E. Fischer, Chem. Phys. Lett. 329, 311 (2000).

[20]

``Intercalation Compounds of Fullerenes I: Synthesis, characterization and solid state properties",

T. Yildirim, O. Zhou, and J. E. Fischer, Phys. Chem. Mater. Low-Dimens. Struct. (Physics of Fullerene-Based and Fullerene-Related Materials - Kluwer Academic Pub.) Volume 23, pg. 23-66 (2000).

[21]

``Intercalation Compounds of Fullerenes II: Structure and superconductivity of alkali metal fullerides",

T. Yildirim, O. Zhou, and J. E. Fischer, Phys. Chem. Mater. Low-Dimens. Struct. (Physics of Fullerene-Based and Fullerene-Related Materials - Kluwer Academic Pub.) Volume 23, pg. 67-133 (2000).

[22]

``Intercalation Compounds of Fullerenes III: Other Fullerides and intercalated nanotubes",

T. Yildirim, O. Zhou, and J. E. Fischer, Phys. Chem. Mater. Low-Dimens. Struct. (Physics of Fullerene-Based and Fullerene-Related Materials - Kluwer Academic Pub.) Volume 23, pg. 249-289 (2000).

[23]

``The structure and dynamics of crystalline durene by neutron scattering and numerical modeling using density functional methods",

M. Plazenet, M. R. Johnson, J. D. Gale, T. Yildirim, G. J. Kearley, H. P. Trommsdorff, and J. M. soler, Chem. Phys. 261, 189 (2000).

[24]

`` Neutron Investigation of Molecular Reorientations in Solid Cubane"

T. Yildirim, P. M. Gehring, D. A. Neumann, P. E. Eaton, and T. Emrick, Phys. Rev. 60, 314 (1999).

[25]

``Neutron scattering study of Na2#2C1#1 in the pressure-temperature plane",

T. Yildirim, D. A. Neumann, S. F. Trevino, and J. E. Fischer, Phys. Rev. B, 60, 1 (1999).

[26]

``Vibrations of cubane molecule: inelastic neutron scattering study and theory",

T. Yildirim, C. Kilic, S. Ciraci, P. M. Gehring, D. A. Neuamm, and P. E. Eaton, Chem. Phys. Lett. 309, 234 (1999).

[27]

``First-principles study of the structure and dynamics of C6#6H6#6, Si6#6H6#6, and Ge6#6H6#6 molecules",

C. Kilic, T. Yildirim, H. Mehrez, and S. Ciraci, J. Phys. Chem. A, 104, 2724 (1999).

[28]

``Quantum dynamics of interstitial H2#2 in solid C1#1",

S. A. FitzGerald, T. Yildirim, L. J. Santodonato, D. A. Neumann, J. R. D. Copley, and J. J. Rush, Phys. Rev. B 60, 6439 (1999).

[29]

``Ordering due to Disorder in Frustrated Quantum Magnetic Systems",

T. Yildirim, Turkish Journal of Physics, 23, 47-76 (1999).

[30]

``The applications of neutron scattering methods to the study of high-temperature protonic conductors",

T. J. Udovic, T. Yildirim, C. Karmonik, and Q. Huang, Mater. Res. Soc. Symp. Proc. 548, 593 (1999).

[31]

``Metallic properties of the ternary fullerides ABa2#2C1#1 (A=K,Rb,Cs)"

K. F. Thier, C. Goze, M. Mehring, F. Rachdi, T. Yildirim, and J. F. Fischer, Phys. Rev. B 59, 10536 (1999).

[32]

``Frustration and Quantum Fluctuations in Heisenberg FCC Antiferromagnets",

T. Yildirim, A. B. Harris, E.F. Shender, Phys. Rev. B 58, 3144 (1998).

[33]

``Solid Cubane: A Brief Summary",

T. Yildirim, P. M. Gehring, D. A. Neumann, P. E. Eaton, and T. Emrick, Carbon 36, 809 (1998).

[34]

``Dynamics of the Perovskite-Based, High-Temperature Proton-Conducting Oxides: Theory and Experiment",

C. Karmonik, T. Yildirim, T. J. Udovic, J. J. Rush, and R. Hempelmann, Materials Research Society Conference Proceeding, Vol. 496, pg. 199 (1998).

[35]

``Structure and lattice dynamics of KC1#1 in the orthorhombic phase: a neutron scattering study",

H. M. Guerrero, R. L. Cappelleti, D. A. Neumann, and T. Yildirim, Chem. Phys. Lett. 297, 265 (1998).

[36]

``Experimental lattice dependence of the density of states in alkali fullerides", J. Robert, P. Petit, T. Yildirim, and J. E. Fischer, Phys. Rev. B 57, 1226 (1998).

[37]

``Muon-spin-relaxation studies of the alkali-fulleride superconductors",

W. A. MacFarlane, R. F. Kiefl, S. Dunsiger, J.E. Sonier, J. Chakhalian, J. E. Fischer, T. Yildirim, and K. H. Chow, Phys. Rev. B 58, 1004-1024 (1998).

[38]

``Single ion anisotropy and Crystal field effects in R2#2CuO10#10 (R =Nd, Pr, Sm)",

R. Sachidanandam, T. Yildirim, A. B. Harris, Amnon Aharony, and Ora Entin-Wohlman,

Phys. Rev. B 56, 260 (1997).

[39]

``Towards a microscopic approach to the intermolecular interaction in solid C1#1",

S. Savin, A. B. Harris, and T. Yildirim, Phys. Rev. B 55, 14182 (1997).

[40]

``C13#13 and Na17#17 NMR Studies of Na2#2C1#1 and Na15#15C1#1 fullerides", F. Rachdi, L. Hajji, M. Galtier, T. Yildirim, J. E. Fischer, and C. Goze, Phys. Rev. B 56, 7831 (1997).

[41]

``Unusual Structure, Phase Transition, and Dynamics of Solid Cubane C6#6H6#6",

T. Yildirim, P. M. Gehring, D. A. Neumann, P. E. Eaton, and T. Emrick, Phys. Rev. Lett 78, 4938 (1997).

[42]

``Three-dimensional ordering in bct antiferromagnets due to quantum disorder",

T. Yildirim, A. B. Harris, E.F. Shender, Phys. Rev. B 53 6455-6477 (1996).

[43]

``T3#3 vs. carrier concentration in cubic Fulleride Superconductors",

T. Yildirim et al., Phys. Rev. Lett. 77, 167 (1996).

[44]

``Synthesis and Properties of Mixed Alkali-Alkaline Earth Fullerides",

T. Yildirim et al, Phys. Rev. B,54, 11981 (1996).

[45]

``Fulleride Superconductors: dependence of T3#3 on average molecular valence in Na2#2Cs8#8C1#1, 18#18",

T. Yildirim et al, Synthetic Metals 77 195-199 (1996).

[46]

``ESR evidence for phonon-mediated resistivity in alkali fullerides",

P. Petit, J. Robert, T. Yildirim, and J. E. Fischer, Phys. Rev. B, 54, R3764 (1996).

[47]

``Parameters controlling superconductivity in doped-fullerenes",

T. Yildirim, in "Recent Advances in the Physics and Chemistry of Fullerenes and Related Materials", K. M. Kadish and R. S. Ruoff eds., the Electrochemical Society Inc., p. 1155 (1996).

[48]

`` Anisotropic Spin Hamiltonians due to Spin-Orbit and Coulomb Exchange Interactions",

T. Yildirim, A. B. Harris, O. E. Wohlman, and A. Aharony, Phys. Rev. B 52, 10239 (1995).

[49]

"Fulleride Superconductors and Orientational Order: T3#3 vs. Lattice Constant in Na2#2Rb8#8Cs12#12C1#1,",

T. Yildirim et al., Solid State Comm. 93, 269, 1995.

[50]

`` C1#1 superconductors: T3#3 vs. lattice constant, orientation, and charge transfer",

T. Yildirim et al., in MRS, Science & Technology of Fullerene Materials, Vol. 359, April 5, 1995.

[51]

``Raman Spectra of Sodium Saturated doped Na8#8C1#1 (x=9.2 and 9.8)",

L. Barbedette, S. Lefrant, T. Yildirim, and J. E. Fischer, p. 460, in Progress in Fullerene Research, ed. by Hans Kuzmany, Jorg Fink, Michael Mehring, and Siegmar Roth, World Scientific, (1995).

[52]

``Symmetry, Spin-Orbit Interactions and Spin Anisotropies",

T. Yildirim, A. B. Harris, O. E. Wohlman, and A. Aharony, Phys. Rev. Lett. 73, 2919, 1994.

[53]

``Spin Structures of Tetragonal Lamellar Copper Oxides",

T. Yildirim, A. B. Harris, O. E. Wohlman, and A. Aharony, Phys. Rev. Lett 72, 3710 (1994).

[54]

`` Symmetry analysis of the 2-a phase of C1#1",

A. B. Harris, R. Sachidanandam, and T. Yildirim, Phys. Rev. B 50, 2622 (1994).

[55]

`` Orientational Order/Disorder in Na8#8C1#1 ",

T. Yildirim et al., page 235, in Progress in Fullerene Research, ed. by Hans Kuzmany, Jorg Fink, Michael Mehring, and Siegmar Roth, World Scientific, 1994.

[56]

`` Intermolecular Potentials and Theory for the Optical Observation of the Lattice Modes in Solid C1#1",

T. Yildirim, page 163, in Progress in Fullerene Research, ed. by Hans Kuzmany, Jorg Fink, Michael Mehring, and Siegmar Roth, World Scientific, 1994.

[57]

``Multipole approach to orientational interactions in solid C1#1",

T. Yildirim, A. B. Harris, S. C. Erwin, and M. R. Pederson, Phys. Rev. B, 48, 1888 (1993).

[58]

``Orientational phases for M7#7C1#1",

T. Yildirim, S. Hong, A. B. Harris, and E. J. Mele, Phys. Rev. B 48, 12262 (1993).

[59]

`` Orientational phase transition in Na8#8C1#1 ( 11#11) ",

T. Yildirim et al., Phys. Rev. Lett. 71, 1383 (1993).

[60]

``A generalized description of the Fröhlich polaron in low dimensionally confined media",

A. Ercelebi and T. Yildirim, in Phonons in Semiconductor Nanostructures, edited by J.-P. Leburton, J. Pascual, and C. S. Torres, NATO ASI Series E, Vol. 236, p. 185-193, 1993.

[61]

``Lattice dynamics of solid C1#1",

T. Yildirim and A. B. Harris, Phys. Rev. B, 46, 7878 - 7896 (1992).

[62]

``Intercalation of sodium heteroclusters into the C1#1 lattice",

T. Yildirim et al., Nature, 350, 568 - 571 (1992).

[63]

``The ground-state description of the optical polaron versus the effective dimensionality in quantum-well-type systems",

T. Yildirim and A. Ercelebi, J. Phys. Condens. Matter. 3 1271-1277 (1991).

[64]

``Weak-coupling optical polaron in QW-confined media",

T. Yildirim and A. Ercelebi, J. Phys. Condens. Matter. 3 4357-4364 (1991).

[65]

``The binding energy of the quasi-two dimensional optical polaron",

T. Yildirim and A. Ercelebi, Doga-Tr., J. of Physics 15, 74-81 (1991).

Last updated: Friday 25th of January 2002 11:26:22 AM
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