Massive and massless Dirac fermions in Pb1-xSnxTe topological crystalline insulator probed by magneto-optical absorption

TL;DR

This study uses magneto-optical absorption to distinguish and analyze surface and bulk Dirac fermions in a PbSnTe topological crystalline insulator, revealing their physical properties and advancing understanding of topological materials.

Contribution

It demonstrates the ability to differentiate and quantify surface and bulk Dirac fermions in a topological crystalline insulator using magneto-optical techniques.

Findings

Successfully distinguished surface and bulk Landau levels.

Extracted physical parameters of Dirac fermions.

Showed high mobility enables detailed Landau level analysis.

Abstract

Dirac fermions in condensed matter physics hold great promise for novel fundamental physics, quantum devices and data storage applications. IV-VI semiconductors, in the inverted regime, have been recently shown to exhibit massless topological surface Dirac fermions protected by crystalline symmetry, as well as massive bulk Dirac fermions. Under a strong magnetic field (B), both surface and bulk states are quantized into Landau levels that disperse as B^1/2, and are thus difficult to distinguish. In this work, magneto-optical absorption is used to probe the Landau levels of high mobility Bi-doped Pb0.54Sn0.46Te topological crystalline insulator (111)-oriented films. The high mobility achieved in these thin film structures allows us to probe and distinguish the Landau levels of both surface and bulk Dirac fermions and extract valuable quantitative information about their physical properties. This work paves the way for future magnetooptical and electronic transport experiments aimed at manipulating the band topology of such materials.