Quantum capacitance of an ultrathin topological insulator film in a magnetic field

TL;DR

This paper theoretically investigates how Zeeman interaction and hybridization affect the quantum magnetocapacitance in ultrathin topological insulator films under magnetic fields, revealing symmetry breaking and oscillation phenomena.

Contribution

It introduces a detailed theoretical analysis of the interplay between Zeeman and hybridization effects on magnetocapacitance in ultrathin topological insulators, aligning with recent experimental observations.

Findings

Breaking of electron-hole symmetry due to Zeeman-hybridization interplay

Observation of beating and splitting of oscillations in magnetocapacitance

Crossover behavior consistent with experimental data

Abstract

We present a theoretical study of the quantum magnetocapacitance of an ultrathin topological insulator film in an external magnetic field. The study is undertaken to investigate the interplay of the Zeeman interaction with the hybridization between the upper and lower surfaces of the thin film. Determining the density of states, we find that the electron-hole symmetry is broken when the Zeeman and hybridization energies are varied relative to each other. This leads to a change in the character of the magnetocapacitance at the charge neutrality point. We further show that in the presence of both Zeeman interaction and hybridization the magnetocapacitance exhibits beating at low and splitting of the Shubnikov de Haas oscillations at high perpendicular magnetic field. In addition, we address the crossover from perpendicular to parallel magnetic field and find consistency with recent experimental data.