Investigators
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George Sawatzky

George Sawatzky

Professor Emeritus

Department of Physics and Astronomy; Department of Chemistry

Research Focus

We use a combination of advanced experimental and theoretical methods in studies of quantum materials exhibiting interesting and not well-understood physical properties. We are particularly interested in using inelastic electron scattering, also known as electron energy-loss spectroscopy, to probe the static and dynamic interactions between charge degrees of freedom in solids, especially at short wavelengths. We also develop new experimental spectroscopic methods such as various forms of x-ray spectroscopies that can provide detailed information concerning the electronic, atomic, and magnetic structure of materials and material interfaces. The development of resonant x-ray reflectometry is one of the most recent highly successful developments. On the theory side, we use and develop further density function band theory methods as well as many body exact diagonalization methods to study the electronic structure of materials and material interfaces.

Current Projects

Q-resolved electron energy-loss spectroscopy of charge excitations in strongly-correlated systems
Screening of short-range Coulomb interactions in materials with strongly non-uniform polarizability
Dynamical charge fluctuations, bond disproportionation, and negative charge transfer gap in systems such as BaBiO3 and the perovskite rare-earth nickelates
Electron-magnon-phonon coupling and their role in high Tc superconductors and topology
Resonant soft x-ray reflectometry and the study of buried interfaces in heterostructures

Selected Publications

S. Johnston, A. Mukherjee, I. Elfimov, M. Berciu, and George A. Sawatzky. Charge Disproportionation without Charge Transfer in the Rare-Earth-Element Nickelates as a Possible Mechanism for the Metal-Insulator Transition. Phys. Rev. Lett. 112, 106404 (2014)
M. T. Czyżyk and G. A. Sawatzky. Local-density functional and on-site correlations: The electronic structure of La₂CuO₄ and LaCuO₃. Phys. Rev. B 49, 14211 (1994)
J. Zaanen, G.A. Sawatzky, J.W. Allen. Band gaps and electronic structure of transition-metal compounds. Phys. Rev. Lett. 55, 418 (1985).

Joseph Salfi

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