Momentum-Resolved Landau-Level Spectroscopy of Dirac Surface State in Bi2Se3

TL;DR

This study uses scanning tunneling spectroscopy to analyze Landau levels of Dirac fermions on Bi2Se3's surface, revealing a field-independent level at the Dirac point and providing insights into surface band dispersion.

Contribution

It presents the first detailed Landau level spectroscopy of Dirac surface states in Bi2Se3, highlighting unique magnetic field responses and spectral features.

Findings

Observation of a field-independent Landau level at the Dirac point

Determination of surface band dispersion through scaling analysis

Detection of fine spectral peaks near the Fermi energy

Abstract

We investigate Dirac fermions on the surface of the topological insulator Bi2Se3 using scanning tunneling spectroscopy. Landau levels (LLs) are observed in the tunneling spectra in a magnetic field. In contrast to LLs of conventional electrons, a field independent LL appears at the Dirac point, which is a hallmark of Dirac fermions. A scaling analysis of LLs based on the Bohr-Sommerfeld quantization condition allowed us to determine the dispersion of the surface band. Near the Fermi energy, fine peaks mixed with LLs appear in the spectra, which may be responsible for the anomalous magneto-fingerprint effect [J. G. Checkelsky et al., Phys. Rev. Lett. 103, 246601 (2009)].