Anomalous Thermal Conductivity of Semi-Metallic Superconductors with Electron-Hole Compensation

TL;DR

This paper investigates how low carrier density and electron-hole compensation influence thermal conductivity in semi-metallic superconductors, revealing an unexpected increase near the upper critical field that explains recent experimental anomalies.

Contribution

It introduces a beyond-quasiclassical approach showing that carrier effects can cause anomalous thermal conductivity behavior near $H_{c2}$ in semi-metallic superconductors.

Findings

Thermal conductivity increases immediately below $H_{c2}$ due to carrier effects.

The model explains the anomalous thermal behavior observed in URu$_2$Si$_2$.

Contrasts with traditional expectations of thermal conductivity decrease near $H_{c2}$.

Abstract

The effects of low carrier density and carrier compensation on mixed-state thermal transport are investigated beyond the quasiclassical approximation. It is shown that, contrary to the usual observations, the interplay of the two effects leads to an {\it increase} in the thermal conductivity immediately below the upper critical field $H_{c2}$. Our result can account for the anomalous behavior of the mixed-state thermal conductivity near $H_{c2}$ recently observed in URu$_2$Si$_2$.