Observation of Zeeman effect in topological surface state with distinct material dependence

TL;DR

This study experimentally observes the Zeeman effect in topological surface states of Bi2Se3 and Sb2Te2Se, revealing distinct material-dependent g-factors, which is crucial for spin manipulation in topological insulators.

Contribution

It provides direct experimental measurements of the Zeeman effect and g-factors in TSS of two topological insulators, highlighting material dependence and enabling spin control strategies.

Findings

Zeeman shift of zero mode Landau level observed in Bi2Se3 and Sb2Te2Se

g-factors of TSS determined as 18 and -6 respectively

Material dependence of g-factors suggests new spin control methods

Abstract

The helical Dirac fermions on the surface of topological insulators host novel relativistic quantum phenomena in solids. Manipulating spins of topological surface state (TSS) represents an essential step towards exploring the theoretically predicted exotic states related to time reversal symmetry (TRS) breaking via magnetism or magnetic field. Understanding Zeeman effect of TSS and determining its g-factor are pivotal for such manipulations in the latter form of TRS breaking. Here, we report those direct experimental observations in Bi2Se3 and Sb2Te2Se by spectroscopic imaging scanning tunneling microscopy. The Zeeman shifting of zero mode Landau level is identified unambiguously by judiciously excluding the extrinsic influences associated with the non-linearity in the TSS band dispersion and the spatially varying potential. The g-factors of TSS in Bi2Se3 and Sb2Te2Se are determined to be 18 and -6, respectively. This remarkable material dependence opens a new route to control the spins in the TSS.