Observation of Shubnikov-de Haas Oscillations in Large-Scale Weyl Semimetal WTe2 Films

TL;DR

This study demonstrates the successful growth of high-quality large-scale WTe2 Weyl semimetal films, revealing quantum oscillations and nontrivial Berry phases, which are promising for future topological quantum devices.

Contribution

The paper reports a method to improve crystalline quality and eliminate Te vacancies in WTe2 films, enabling observation of Shubnikov-de Haas oscillations and Berry phases.

Findings

Observation of Shubnikov-de Haas oscillations in WTe2 films

High Hall mobility reaching over 1200 cm2V-1s-1

Identification of nontrivial Berry phase through Landau fan analysis

Abstract

Topological Weyl semimetal WTe2 with large-scale film form has a promising prospect for new-generation spintronic devices. However, it remains a hard task to suppress the defect states in large-scale WTe2 films due to the chemical nature. Here, we significantly improve the crystalline quality and remove the Te vacancies in WTe2 films by post annealing. We observe the distinct Shubnikov-de Haas quantum oscillations in WTe2 films. The nontrivial Berry phase can be revealed by Landau fan diagram analysis. The Hall mobility of WTe2 films can reach 1245 cm2V-1s-1 and 1423 cm2V-1s-1 for holes and electrons with the carrier density of 5 * 10^19 cm^-3 and 2 * 10^19 cm^-3, respectively. Our work provides a feasible route to obtain high-quality Weyl semimetal films for the future topological quantum device applications.