Transport anomalies across the quantum limit in semimetallic Bi$_{0.96}$Sb$_{0.04}$

TL;DR

This study investigates electronic transport in Bi$_{0.96}$Sb$_{0.04}$, revealing quantum oscillations, a low-field quantum limit, and an ultraquantum anomaly likely caused by many-body effects beyond single-particle models.

Contribution

It provides new insights into quantum transport phenomena and many-body effects in dilute semimetallic bismuth-antimony alloys at high magnetic fields.

Findings

Quantum oscillations in resistivity, Hall, Nernst, and Seebeck responses.

Quantum limit occurs at as low as 3T for field along trigonal axis.

Detection of an ultraquantum anomaly linked to many-body effects.

Abstract

We report on a study of electronic transport in semi-metallic Bi$_{0.96}$Sb$_{0.04}$. At zero field, the system is a very dilute Fermi liquid displaying a T$^{2}$ resistivity with an enhanced prefactor. Quantum oscillations in resistivity as well as in Hall, Nernst and Seebeck responses of the system are detectable and their period quantifies the shrinking of the Fermi surface with antimony doping. For a field along the trigonal axis, the quantum limit was found to occur at a field as low as 3T. An ultraquantum anomaly at twice this field was detected in both charge transport and Nernst response. Its origin appears to lie beyond the one-particle picture and linked to unidentified many-body effects.