High-field immiscibility of electrons belonging to adjacent twinned bismuth crystals

TL;DR

This study reveals that in high magnetic fields, adjacent twinned bismuth crystals exhibit electron immiscibility with a significant chemical potential difference, explained by a charge-accumulating barrier at twin boundaries.

Contribution

It demonstrates that twinned bismuth crystals can maintain separate chemical potentials under high magnetic fields, introducing a new understanding of electron behavior at twin boundaries.

Findings

Chemical potential difference up to 68 meV at 65 T

Electron immiscibility across twin boundaries

Charge accumulation forms a barrier similar to a Schottky junction

Abstract

Bulk bismuth has a complex Landau spectrum. The small effective masses and the large g-factors are anisotropic. The chemical potential drifts at high magnetic fields. Moreover, twin boundaries further complexify the interpretation of the data by producing extra anomalies in the extreme quantum limit. Here, we present a study of angle dependence of magnetoresistance up to 65 T in bismuth complemented with Nernst, ultrasound, and magneto-optic data. All observed anomalies can be explained in a single-particle picture of a sample consisting of two twinned crystals tilted by 108$^{\circ}$ and with two adjacent crystals keeping their own chemical potentials despite a shift between chemical potentials as large as 68 meV at 65 T. This implies an energy barrier between adjacent twinned crystals reminiscent of a metal-semiconductor Schottky barrier or a p-n junction. We argue that this barrier is built by accumulating charge carriers of opposite signs across a twin boundary.