Modulation of crystal and electronic structures in topological insulators by rare-earth doping

TL;DR

This study investigates how rare-earth doping, specifically Sm, alters the crystal and electronic structures of topological insulators, affecting their magnetotransport properties and Fermi surface topology, with implications for exotic topological effects.

Contribution

It demonstrates that Sm doping modifies the crystal and electronic structures of topological insulators, enabling manipulation of the Fermi surface and potential realization of exotic topological phenomena.

Findings

Observation of Shubnikov de Haas oscillations indicating mixed bulk and surface contributions.

Identification of a three-dimensional Fermi surface topology through angular dependence.

Theoretical calculations showing structural and electronic changes due to Sm doping.

Abstract

We study magnetotransport in a rare earth doped topological insulator, Sm0.1Sb1.9Te3 single crystals, under magnetic fields up to 14 T. It is found that that the crystals exhibit Shubnikov de Haas oscillations in their magneto-transport behaviour at low temperatures and high magnetic fields. The SdH oscillations result from the mixed contributions of bulk and surface states. We also investigate the SdH oscillations in different orientations of the magnetic field, which reveals a three dimensional Fermi surface topology. By fitting the oscillatory resistance with the Lifshitz Kosevich theory, we draw a Landau-level fan diagram that displays the expected nontrivial phase. In addition, the density functional theory calculations shows that Sm doping changes the crystal structure and electronic structure compared with pure Sb2Te3. This work demonstrates that rare earth doping is an effective way to manipulate the Fermi surface of topological insulators. Our results hold potential for the realization of exotic topological effects in magnetic topological insulators.