Thursday, December 27, 2012

1212.6174 (Christophe Berthod et al.)

Non-Drude universal scaling laws for the optical response of local Fermi
liquids
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Christophe Berthod, Jernej Mravlje, Xiaoyu Deng, Rok Žitko, Dirk van der Marel, Antoine Georges
We investigate the frequency and temperature dependence of the low-energy electron dynamics in a Landau Fermi-liquid with a local self-energy. We show that the frequency and temperature dependence of the optical conductivity obeys a universal scaling form, for which an explicit analytical expression is obtained. For the optical conductivity and the associated memory function, we obtain a number of surprising features which differ qualitatively from the Drude-model and are universal characteristics of a Fermi liquid. Different physical regimes of scaling are identified, with marked non-Drude features in the regime where hbar {\omega} ~ kB T. These analytical results for the optical conductivity are compared to numerical calculations for the doped Hubbard model within dynamical mean-field theory. For the 'universal' low energy electrodynamics, we obtain perfect agreement between numerical calculations and analytical scaling laws. Both results show that the optical conductivity displays a non-Drude 'foot', which could be easily mistaken as a signature of breakdown of the Fermi liquid, while it actually is a striking signature of its applicability. The aforementioned scaling laws provide a quantitative tool for the experimental identification and analysis of the Fermi-liquid state using optical spectroscopy, and a powerful method for the identification of alternative states of matter, when applicable.
View original: http://arxiv.org/abs/1212.6174

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