Bulk Fermi surface coexistence with Dirac surface state in Bi$_2$Se$_3$: a comparison of photoemission and Shubnikov-de Haas measurements

TL;DR

This study compares photoemission and magnetotransport measurements in Bi2Se3, revealing coexistence of bulk Fermi surfaces with Dirac surface states and highlighting discrepancies at low carrier densities.

Contribution

It demonstrates the quantitative agreement of ARPES and SdH in measuring bulk properties and discusses the coexistence of bulk and surface states in topological insulators.

Findings

SdH and ARPES agree on effective mass and bulk dispersion

Bulk 3D Fermi surface observed at low carrier densities

Discrepancies in Fermi level position at low carrier densities

Abstract

Shubnikov de Haas (SdH) oscillations and Angle Resolved PhotoEmission Spectroscopy (ARPES) are used to probe the Fermi surface of single crystals of Bi2Se3. We find that SdH and ARPES probes quantitatively agree on measurements of the effective mass and bulk band dispersion. In high carrier density samples, the two probes also agree in the exact position of the Fermi level EF, but for lower carrier density samples discrepancies emerge in the position of EF. In particular, SdH reveals a bulk three-dimensional Fermi surface for samples with carrier densities as low as 10^17cm-3. We suggest a simple mechanism to explain these differences and discuss consequences for existing and future transport studies of topological insulators.