Condensed Matter Physics Seminar

2 p.m., Thursday, April 26, 2007
Room 1201, Physics Building

 Pseudogaps and Fermi arcs:A cluster dynamical mean field theory description of Mottness

Tudor Stanescu

(CMTC, University of Maryland)

Abstract:  Within the Hubbard model, we investigate the properties of a strongly correlated metal in the proximity of a Mott insulating phase, using a cluster generalization of the dynamical mean field theory. We find that short range correlations determine the opening of a Mott gap at half filling and the appearance on a k-dependent pseudogap at finite doping. When the gaps are opened, the system is characterized by a divergence of the zero frequency electron self-energy at certain momenta in the Brillouin zone corresponding to a surface of zeros of the single particle Green function. The interplay between this surface of zeros and the surface of infinities (the Fermi surface) leads to the appearance of Fermi arcs. In the superconducting state, we find that the photoemission energy-gap can be naturally decomposed into two components: one is generated by d-wave superconductivity and formally described by the anomalous self-energy, wile the other, stemming from the proximity of the Mott insulator, is described by the normal self-energy and evolves into the normal-state pseudogap. In the underdoped regime the first component dominates the nodal points and decreases with decreasing doping, while the second dominates the antinodes and has an opposite doping dependence.
Host:  Galitski
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