Detailed structural and topological analysis of SnBi2Te4 single crystal

TL;DR

This paper reports the synthesis, detailed structural and topological analysis, and experimental and theoretical characterization of SnBi2Te4 single crystals, revealing its topological non-trivial properties and weak anti-localization effects.

Contribution

It provides a comprehensive synthesis and multi-faceted analysis of SnBi2Te4, establishing its topological nature through experimental measurements and first-principles calculations.

Findings

SnBi2Te4 exhibits non-saturating magnetoresistance up to 12 T.

Weak anti-localization effect confirmed via HLN formalism at 2 K.

Topological non-triviality verified through DFT calculations and Z2 invariants.

Abstract

We report herein the successful synthesis of the topological material SnBi2Te4 in single-crystal form. Phase purity and unidirectional growth are evident from X-ray diffraction (XRD) patterns acquired from a powdered sample and a crystal flake. The crystalline morphology has also been visualized by acquiring a field-emission scanning electron microscope (FESEM) image. The crystal has been thoroughly characterized by means of Raman spectroscopy and X ray photoelectron spectroscopy (XPS) measurements. The topological properties of SnBi2Te4 have been probed through magneto-transport measurements. SnBi2Te4 has been found to exhibit a small but non-saturating magneto-resistance (MR) up to 12 T. The low-field magnetoconductivity (MC) of SnBi2Te4 at 2 K can be well explained through the Hikami Larkin Nagaoka (HLN) formalism, which confirms the presence of a weak anti-localization (WAL) effect in its crystal. Moreover, the non-trivial topological character has been evidenced through first-principles calculations using density functional theory (DFT), with and without spin-orbit coupling (SOC) protocols. A significant change in the bulk electronic band structure is observed upon the inclusion of SOC parameters, signifying the topological properties of SnBi2Te4. Its topological non-trivial character has also been verified through the calculation of Z2 invariants and the surface states spectrum in the (111) plane.