Thickness-dependent electronic structure in WTe2 thin films

We study the electronic structure of WTe2 thin films with different thicknesses. High-quality thin-film samples

are obtained with carrier mobility up to 5000 cm2 V−1 s−1, which enables us to resolve the four main Fermi

pockets from Shubnikov–de Haas (SdH) oscillations. Angle-resolved SdH oscillations show that the WTe2 thin

films cross from three-dimensional to two-dimensional electronic systems at a thickness of ∼ 20 nm. Using the

field effect, the nature of the Fermi pockets in thin-film WTe2 is identified, and the evolution of SdH oscillation

frequencies is traced over different sample thicknesses. It is found that the frequencies dramatically decrease at

a thickness of approximately 12 nm, which indicates the onset of finite-size effects on the band structure. Our

work pins down two critical length scales of the thickness-dependent electronic structure in WTe2 thin films.