Tunable Γ−K Valley Populations in Hole-Doped Trilayer WSe2

Abstract

We present a combined experimental and theoretical study of valley populations in the valence bands of trilayer WSe_{2}. Shubnikov-de Haas oscillations show that trilayer holes populate two distinct subbands associated with the K and Γ valleys, with effective masses 0.5m_{e} and 1.2m_{e}, respectively; m_{e} is the bare electron mass. At a fixed total hole density, an applied transverse electric field transfers holes from Γ orbitals to K orbitals. We are able to explain this behavior in terms of the larger layer polarizability of the K orbital subband.

Metal-chalcogen bond-length induced electronic phase transition from semiconductor to topological semimetal in ZrX2 ( X=Se and Te)

“…Tunable band gaps in layered TMDCs is one of the major research topics in recent days from both the theory and experiment [39][40][41][42]. It is known that the band gaps in IVB TMDCs (TiX 2 , ZrX 2 and HfX 2 , where X = S, Se, and Te) increase with the strain [43].…”

Recent Advances in Quantum Effects of 2D Materials

“…The QH plateaux sequence measured in the 2D WSe 2 shows a twofold degeneracy and is insensitive to the in‐plane component of the B ‐field . This arises from the large SOC induced extremely large splitting energy (≈640 meV in 1L‐WSe 2 and ≈80 meV in 2L‐WSe 2 ) and the mirror symmetry, whereby the hole spin is locked to the out‐of‐plane direction and therefore only responds to the B ⊥ .…”

“…c) Quantum Hall plateaus ( R xy ) and SdH oscillations ( R xx ) as a function of magnetic field in a bilayer WSe 2 device at different p‐doping level: (left) p = 3.9 × 10 12 cm −2 showing quantum Hall states at predominantly odd filling factors and (right) 5.3 × 10 12 cm −2 , showing quantum Hall states at predominantly even filling factors. Reprinted with permission . Copyright 2017, American Physical Society.…”

“…Specifically, as E z /E c close to an even/odd integer, the filling factors are predominantly odd/even. The g * value is largely enhanced with reduced carrier density due to the strong electron‐electron interactions . For multilayer WSe 2 , Xu et al.…”

Versatile construction of van der Waals heterostructures using a dual-function polymeric film

“…an der Waals (vdW) heterostructures are an exciting playground for scientific discoveries among different disciplines [1][2][3][4][5][6][7][8][9][10][11] . These structures are made by stacking different layered materials that are held together by vdW forces.…”