Broken mirror symmetry tuned topological transport in PbTe/SnTe heterostructures

TL;DR

This study demonstrates how breaking mirror symmetry in PbTe/SnTe heterostructures modulates topological surface states, leading to giant magnetoresistance and potential applications in magneto-electronics and spintronics.

Contribution

It reveals the influence of structural phase transitions and symmetry breaking on topological surface states and magnetoresistance in TCI heterostructures.

Findings

Giant linear magnetoresistance up to 2150% at 2 K under 14 T

Structural phase transition of SnTe lattice below 100 K

Broken mirror symmetry causes Dirac gap opening and magnetoresistance

Abstract

The tunability of topological surface states and controllable opening of the Dirac gap are of great importance to the application of topological materials. In topological crystalline insulators (TCIs), crystal symmetry and topology of electronic bands intertwine to create topological surface states and thus the Dirac gap can be modulated by symmetry breaking structural changes of lattice. By transport measurement on heterostructures composed of p-type topological crystalline insulator SnTe and n-type conventional semiconductor PbTe, here we show a giant linear magnetoresistance (up to 2150% under 14 T at 2 K) induced by the Dirac Fermions at the PbTe/SnTe interface. In contrast, PbTe/SnTe samples grown at elevated temperature exhibit a cubic-to-rhombohedral structural phase transition of SnTe lattice below 100 K and weak antilocalization effect. Such distinctive magneto-resistance behavior is attributed to the broken mirror symmetry and gapping of topological surface states. Our work provides a promising application for future magneto-electronics and spintronics based on TCI heterostructures.