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arXiv · 2410.05671

On the Amplitude of Vortex Entropy: A Semiclassical Treatment

Yehao Guo·Dong Qiu·Haiwen Liu·Jie Xiong
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Abstract

Despite a long history of Nernst effect in superconductors, a satisfactory theory on its amplitude in vortex liquid phase is still absent. The central quantity of vortex Nernst signals is the entropy $s_{\phi}$ carried by each vortex. Here we show a semiclassical treatment based on London equation and Pippard nonlocal generalization. The derived $s_{\phi}$ is a function of both temperatures and magnetic fields. Its magnitude $s_{\phi}^{amp}$ scales with normal-state conductivity ${\sigma}_n$. Estimations based on our formula show good consistency with experimentally determined values. In dirty limit, the relation is further simplified into a Wiedemann-Franz-like ratio $s_{\phi}^{amp}/{\sigma}_n \propto k_B \ln 2/{\sigma}_Q$ if taking parameter values deduced from Homes' law, where ${\sigma}_Q=4e^2/h$ is two-dimensional quantum conductivity. We also address related issues, including bounds to $s_{\phi}$, the Nernst signal and viscosity-entropy density ratio, which are all expressed in fundamental physical constants.

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Yehao Guo, Dong Qiu, Haiwen Liu, Jie Xiong. 2024-10-08. On the Amplitude of Vortex Entropy: A Semiclassical Treatment. https://arxiv.org/abs/2410.05671

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