John Emrich Klepeis

Research Interests

Development and application of first-principles all-electron density functional and semi-empirical tight-binding techniques to the electronic structure of surfaces and interfaces, semiconductors, f-electron materials, wide bandgap insulators, nanoparticles, intermetallic compounds, and materials at high pressure.  Equation of state of materials.

Professional Background

John Klepeis is a theoretical and computational condensed matter physicist and Group Leader of the Equation of State (EOS) and Materials Theory Group in the Physics Division of the Physical and Life Sciences Directorate at LLNL, where he has been since 1989. He received his B.S. degree from the School of Applied and Engineering Physics at Cornell University in 1985. His graduate work was carried out in the Department of Applied Physics at Stanford University under Professor Walter A. Harrison. He obtained his M.S. degree in 1987 and his Ph.D. in 1989. At Stanford John studied Coulomb effects in semiconductor systems using self-consistent tight-binding electronic structure calculations. In particular, he applied this methodology to dopants in semiconductors, semiconductor heterojunctions, and metal-semiconductor interfaces. His thesis, entitled, Self-consistent electronic structure of semiconductor systems, shed light on the underlying principles that determine the valence band offset in heterojunctions and the Schottky barrier in metal-semiconductor contacts.

Upon graduation from Stanford in 1989 John accepted a post-doctoral position in the Condensed Matter Physics Division at LLNL. While at LLNL John has been a visiting scientist at the Fritz Haber Institute in Berlin, Germany with the group of Professor Mathias Scheffler for three months in the fall of 1991 and on three later occasions at the University of Erlangen-Nuremberg in Erlangen, Germany with the group of Professor Oleg Pankratov. At LLNL John has pursued the development and application of both first-principles all-electron density functional and semi-empirical tight-binding electronic structure techniques to a wide variety of condensed matter systems. Areas of interest have included the interpretation of experimental spectroscopic studies of surface, interface, and nanoparticle systems, the determination of the equation-of-state and thermodynamic properties of f-electron materials and the study of the elastic properties of materials as a function of pressure.  John has been the Group Leader of the EOS & Materials Theory Group since 2006.