Berry phase of non-ideal Dirac fermions in topological insulators

TL;DR

This paper presents a general method to analyze Shubnikov-de Haas oscillations in topological insulators, enabling clearer identification of Dirac fermions' Berry phase in realistic experimental conditions.

Contribution

It introduces a comprehensive scheme for interpreting SdH oscillation phase factors in non-ideal topological insulator surface states, improving the identification of Dirac fermions.

Findings

Proposed a new scheme for analyzing phase factors in SdH oscillations.

Demonstrated how to distinguish Dirac nature in experimental data.

Enhanced understanding of surface state properties in topological insulators.

Abstract

A distinguishing feature of Dirac fermions is the Berry phase of $\pi$ associated with their cyclotron motions. Since this Berry phase can be experimentally assessed by analyzing the Landau-level fan diagram of the Shubnikov-de Haas (SdH) oscillations, such an analysis is widely employed in recent transport studies of topological insulators to elucidate the Dirac nature of the surface states. However, the reported results have usually been unconvincing. Here we show a general scheme for describing the phase factor of the SdH oscillations in realistic surface states of topological insulators, and demonstrate how one could elucidate the Dirac nature in the real experimental data.