Unexpected Metallic Phases In Models Containing Electron-Phonon Interactions

R. Torsten Clay, Assistant Professor of Physics & Astronomy, Mississippi State University

One common feature of unconventional superconductors is the proximity of the metallic or superconducting phase to a phase region with "unusual" insulating properties. These materials are often low dimensional, and to understand the insulating phases one must include the effect of electron-electron (e-e) interactions. For many materials, and especially for molecular superconductors, electron-phonon (e-ph) interactions are important as well. Including both interactions greatly increases both the complexity of relevant models as well as the techniques needed to solve them. We consider a simple model of interacting electrons with both e-e and e-ph interactions, the Hubbard-Holstein model. While it was previously believed that both interactions promote insulating behavior, we show that together they can mediate an unusual metallic phase.

Publication: RT Clay, RP Hardikar, Physical Review Letters 95, 096401 (2005)

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