Signatures of surface states in bismuth at high magnetic fields

TL;DR

This paper explains unusual high-field oscillations in bismuth as arising from surface states with strong spin-orbit coupling, challenging previous interpretations of electron fractionalization.

Contribution

It provides a surface state-based explanation for high-field oscillations in bismuth, supported by quantitative agreement with experimental data.

Findings

Oscillations match surface state theory predictions

Surface electrons exhibit significant spin-orbit interaction

Proposes tests involving Zeeman coupling and sample thickness

Abstract

Electrons in a metal subject to magnetic field commonly exhibit oscillatory behavior as the field strength varies, with a period set by the area of quantized electronic orbits. Recent experiments on elemental bismuth have revealed oscillations for fields above 9 tesla that do not follow this simple dependence and have been interpreted as a signature of electron fractionalization in the bulk. We argue instead that a simple explanation in terms of the surface states of bismuth exists when additional features of the experiment are included. These surface electrons are known to have significant spin-orbit interaction. We show the observed oscillations are in quantitative agreement with the surface theory, which we propose to test by studying the effect of the Zeeman coupling in higher fields, dependence on the field orientation, and the thickness of the samples.