Optical Conductivity in Mott-Hubbard Systems

Abstract

We study the transfer of spectral weight in the optical spectra of a strongly correlated electron system as a function of temperature and interaction strength. Within a dynamical mean field theory of the Hubbard model that becomes exact in the limit of large lattice coordination, we predict an anomalous enhancement of spectral weight as a function of temperature in the correlated metallic state and report on experimental measurements which agree with this prediction in V 2 O 3 . We argue that the optical conductivity anomalies in the metal are connected to the proximity to a crossover region in the phase diagram of the model. 71.27.+a, 71.30.+h, 78 Typeset using REVT E X 1

Dynamical mean–field studies of metal–insulator transitions

“…Several quantitative comparisons between the physics of three dimensional transition metal oxides and the one band Hubbard model have already been performed (Kotliar & Kajueter 1996, Rozenberg et al 1995. For example, the doping dependence of the electronic specific heat, the resistivity and the Hall coefficient in La x Sr 1−x T iO 3 can be explained by the one band Hubbard model without adjustable parameters after the values of U and D have been extracted from photoemission data (Kajueter et.…”

“…1996). Similarly, the single band Hubbard model can describe the temperature dependence of both, the optical and the DC-conductivity in V 2 O 3 (Rozenberg et al 1995).…”

Transfer of spectral weight in spectroscopies of correlated electron systems

“…The Appendix describes an algorithm to convert the sum of two given continued fractions into a new continued fraction which we use to extend the ED method to the models we treat in this paper. Part of the theoretical results in section IV were announced in a recent letter 21 . The optical conductivity of the Anderson model and the Hubbard model were considered previously by Jarrell et al using the Qauntum Monte Carlo and Maximum Entropy methods.…”

High-frequency thermoelectric response in correlated electronic systems

“…In the infinite dimension limit, a significant simplification is achieved because all nonlocal irreducible vertex collapse and only the first bubble diagram survives 19,23 . This simplification leads to…”