- Modeling and theory of the atomic and electronic structure of metal-oxide semiconductor interfaces; prediction of properties of advanced gate stacks for CMOS applications; modeling of defects in these systems.
- Modeling and ab-initio calculations of defects in graphene; modeling of graphene growth.
- Theory, modeling, and simulation of the dielectric properties of complex oxides; models for local structure in these materials.
- Generation of atomistic models based on first-principles calculations; Monte Carlo and molecular dynamics simulations of such models; computational phase diagrams for structural phase transitions.
Figure 1(left): Atomistic models of advanced gate stacks: (a) Si-SiO2; (b) SiO2-HfO2; (c) Si-SiO2-HfO2-SiO2; (d) vacuum-Si-SiO2-HfO2. Figure 2(right): Bilayer graphene containing an intercolated Mo impurity.
Figure 3: Simulated phase diagram of PbSc1/2Nb1/2O3 under pressure, demonstrating a relaxor state.
Postdoctoral Research Opportunities
Computational Studies of Dielectrics, Ferroelectrics, and other Functional Oxides. Certain oxides, especially those with perovskite or related structures, exhibit remarkable physical properties, such as large dielectric constants, large piezoelectric coefficients, relaxor ferroelectricity, and colossal magnetoresistance. Materials with optimal properties are generally solid solutions, often involving four or more different metal ions. Research opportunities exist in the systematic development of advanced models for the prediction of the above physical properties in such solid solutions....
First-Principle Calculations of Defects in Electronic Materials.Many of the current challenges in integration of new materials into nanoscale electronic devices concern the nature of the defects in these materials. For example, oxygen vacancies in HfO2 (hafnia) are believed to decrease the channel mobility of Si integrated circuit transistor devices, thereby causing threshold voltage instabilities. First-principles (FP) calculations can yield information about defect properties that can potentially provide solutions to such materials problems. ...
Awards and Honors
- NRC Postdoctoral Fellowship, 1998-2000
- Chateaubriand Fellowship, France, 1993-1995
- A. D. White Fellowship, Cornell University, 1988-1991
- National Science Foundation Graduate Fellowship 1988-1993
2001-present: Physicist, Ceramics Division, NIST
2000-2001: Research Associate, Catholic University of America
1998-2000: NRC Postdoctoral Fellow, Ceramics Division, NIST
1995-1998: Postdoctoral Research Associate, Yale University
1993-1995: Postdoctoral Research Associate, Université Paris-Sud
Ph.D., Physics, Cornell University, 1994
M.S., Physics, Cornell University, 1991
B.S., Physics, SUNY at Buffalo, 1988