Changes of Fermi Surface Topology due to the Rhombohedral Distortion in SnTe

TL;DR

This study investigates how pressure-induced suppression of ferroelectric distortion in SnTe alters its Fermi surface topology, revealing significant electronic structure changes and a persistent linear magnetoresistance.

Contribution

It combines quantum oscillations, DFT calculations, and ARPES to show how pressure affects Fermi surface topology and electronic properties in SnTe.

Findings

Fermi surface changes at pressures above 10 kbar due to suppression of polar transition

Large decrease in resistivity and Hall effect upon pressure application

Persistent linear magnetoresistance linked to high curvature regions of the Fermi surface

Abstract

Stoichiometric SnTe is theoretically a small gap semiconductor that undergoes a ferroelectric distortion on cooling. In reality however, crystals are always non-stoichiometric and metallic; the ferroelectric transition is therefore more accurately described as a polar structural transition. Here we study the Fermi surface using quantum oscillations as a function of pressure. We find the oscillation spectrum changes at high pressure, due to the suppression of the polar transition and less than 10 kbar is sufficient to stabilize the undistorted cubic lattice. This is accompanied by a large decrease in the Hall and electrical resistivity. Combined with our density functional theory (DFT) calculations and angle resolved photoemission spectroscopy (ARPES) measurements this suggests the Fermi surface $L$-pockets have lower mobility than the tubular Fermi surfaces that connect them. Also captured in our DFT calculations is a small widening of the band gap and shift in density of states for the polar phase. Additionally we find the unusual phenomenon of a linear magnetoresistance that exists irrespective of the distortion that we attribute to regions of the Fermi surface with high curvature.