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arXiv · 1511.02213

Fate of the Wiedemann-Franz law near quantum critical points of electron systems in solids

V. A. Khodel·J. W. Clark·V. R. Shaginyan·M. V. Zverev
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Abstract

We introduce and analyze two different scenarios for violation of the Wiedemann-Franz law in strongly correlated electron systems of solids, close to a topological quantum critical point (TQCP) where the density of states $N(0)$ diverges. The first, applicable to the Fermi-liquid (FL) side of the TQCP, involves a transverse zero-sound collective mode that opens a new channel for the thermal conductivity, thereby enhancing the Lorenz number $L(0)$ relative to the value $L_0=π^2k^2_B/3e^2$ dictated by conventional FL theory. The second mechanism for violation of the WF law, relevant to the non-Fermi-liquid (NFL) side of the TQCP, involves the formation of a flat band and leads instead to a reduction of the Lorenz number.

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V. A. Khodel, J. W. Clark, V. R. Shaginyan, M. V. Zverev. 2015-11-06. Fate of the Wiedemann-Franz law near quantum critical points of electron systems in solids. https://doi.org/10.1134/s0021364015240066

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