Observation of Shubnikov-de Haas Oscillations in Large-Scale Weyl Semimetal WTe_2 Films

Topological Weyl semimetal WTe_2 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 WTe_2 films due to the chemical nature. Here we significantly improve the crystalline quality and remove the Te vacancies in WTe_2 films by post annealing. We observe the distinct Shubnikov-de Haas quantum oscillations in WTe_2 films. The nontrivial Berry phase can be revealed by Landau fan diagram analysis. The Hall mobility of WTe_2 films can reach 1245 cm^2V^-1s^-1 and 1423 cm^2V^-1s^-1 for holes and electrons with the carrier density of 5\times 10^19 cm^-3 and 2\times 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.