Large-Area Freestanding Weyl Semimetal WTe_2 Membranes

We report a universal transfer methodology for producing artificial heterostructures of large-area freestanding single-crystalline WTe₂ membranes on diverse target substrates.The transferred WTe₂ membranes exhibit a nondestructive structure with a carrier mobility comparable to that of as-grown films(～179–1055 cm²·V^?1·s^?1).Furthermore,the transferred membranes show distinct Shubnikov–de Haas quantum oscillations as well as weak localization/weak anti-localization.These results provide a new approach to the development of atom manufacturing and devices based on atomic-level,large-area topological quantum films.     

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

Topological Weyl semimetal WTe2 with large-scale Him 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 1245cm^2V^-1s^-1 and 1423cm^2V^-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.