Nanotechnology interdisciplinary research team grant
National Science Foundation
DMR-0210717

Computational design and optimization of nanoscale spintronic and thermoelectric devices (2002-2007)

This project is developing computational methods to optimize the properties of spintronic devices and investigate new proposals for low-temperature thermoelectric coolers. Both devices are constructed from ultrathin layers of different materials stacked into an inhomogeneous multilayered device, with current flowing perpendicular to the layers. The presence of interfaces strongly modifies the bulk properties of the devices and determines their ultimate performance. We combine density functional theory with many-body transport to study both linear and nonlinear responses of these devices.

Team members

Jim Freericks (Department of Physics, Georgetown University), Principal Investigator

Prof. Freericks is an expert in transport theory for strongly correlated systems. He employs the dynamical mean field theory to self-consistently solve the many-body problem for inhomogeneous devices, and then determine transport coefficients like the resistance, thermopower and thermal resistance. He has worked in this area of research since 1992.

Amy Liu (Department of Physics, Georgetown University), Co-Principal Investigator

Prof. Liu is an expert in density functional theory, working on problems like phonons and superconductivity, ultrahard materials, materials under extreme pressure, and magnetism. She examines interfaces between different materials with supercell calculations, and determines the input parameters for the many-body transport formalism. She has worked in this field since 1988.

Barbara Jones (IBM, Almaden Research Center) Co-Principal Investigator

Dr. Jones works on spin-dependent transport and spintronics. Her current focus is on current-induced magnetic domain-wall motion in nanopillars and her work is often tied closely to experimental work. She is also an expert on giant magneto resistance and the Kondo effect. Dr.. Jones is also a member of the advisory board of the Industrial Leadership in Physics program, which is a Ph.D. program at Georgetown University, designed to train students who plan to work in industry after graduation.

Other Senior Personnel

Veljko Zlatic (Institute of Physics, Zagreb, Croatia)

Dr. Zlatic is involved with developing the many-body transport theory both for linear and nonlinear responses. He is an expert on the Falicov-Kimball model and on the single-impurity Anderson model. He also has spent significant time working on the problem of thermal transport. Dr. Zlatic visits Georgetown University for approximately one month every year, and hosts team members in Croatia for collaborations.

Postdoctoral Fellows

Denis Demchenko (2002--2005)

Dr. Demchenko works on thermal transport problems and on the metal-insulator transition away from particle-hole symmetry. He also works on DFT problems ranging from nanomagnets to magnetic metal/semiconductor interfaces. Currently at the Lawrence Berkeley Laboratory.

Volodmyr Turkowski (2003--2006)

Dr. Turkowski is working on developing a nonequilibrium formalism for the many-body problem and solving it for the Falicov-Kimball model. This project forms the backbone for a nonlinear response formalism for strongly correlated nanostructures.

Ilan Schnell (2005--2006)

Dr. Schnell is working on modeling MgB₂-based Josephson junctions with a MgO barrier. He is using DFT calculations to map onto tight-binding calculations for transport.

Hand Zenia (2007)

Dr. Zenia is working on a two-band model for ion-damaged MgB₂ Josephson junctions and on incorporating the numerical renormalization group approach into transport across multilayers.

Graduate Students

Simon Hale (2006-- , Ph.D. candidate, Georgetown)

Simon is currently on an apprenticeship at IBM where he is working on problems related to magnetic storage. He has also been working on trying to understand the numerical renormalization group algorithm, and will likely apply this work to examining thermoelectric transport in correlated materials within the dynamical mean-field theory approach.

Alexander Joura (2002-- , Ph.D. candidate, Georgetown)

Sasha has worked on thermal transport problems, and at IBM's Almaden Research Center on Kondo problems that apply to the experimental work of Don Eigler's group. He is currently working on steady state nonequilibrium dynamical mean-field theory.

Ling Chen (2002--2006, Ph.D. candidate, Georgetown)

Ling has worked on charge-density-waves and on magnetic domain wall motion in ferromagnetic nanostructures (while on his apprenticeship at IBM). He has worked on electronic charge reconstruction in strongly correlated systems. He is currently on a leave of absence from the university.

Progress Reports

2003: Materials Theory [highlight], NIRT grantees conference [overview] [highlight];
2004: Materials Theory [highlight], NIRT grantees conference [overview];
2005;
2006