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arXiv · 1912.04919

Wiedemann-Franz law in a non-Fermi liquid and Majorana central charge: Thermoelectric transport in a two-channel Kondo system

Gerwin A. R. van Dalum·Andrew K. Mitchell·Lars Fritz
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Abstract

Quantum dot devices allow one to access the critical point of the two-channel Kondo model. The effective critical theory involves a free Majorana fermion quasiparticle localized on the dot. As a consequence, this critical point shows both the phenomenon of non-Fermi liquid physics and fractionalization. Although a violation of the Wiedemann-Franz law is considered a defining feature of non-Fermi liquid systems, we show by exact calculations that it holds at the critical point, providing a counterexample to this lore. Furthermore, we show that the fractionalized Majorana character of the critical point can be unambiguously detected from the heat conductivity, opening the door to a direct experimental measurement of the elusive Majorana central charge $c=\tfrac{1}{2}$.

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Gerwin A. R. van Dalum, Andrew K. Mitchell, Lars Fritz. 2020-07-08. Wiedemann-Franz law in a non-Fermi liquid and Majorana central charge: Thermoelectric transport in a two-channel Kondo system. https://doi.org/10.1103/physrevb.102.041111

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