Tunable $\mathrm{\ensuremath{\Gamma}}\ensuremath{-}K$ Valley Populations in Hole-Doped Trilayer ${\mathrm{WSe}}_{2}$

Editors' Suggestion

Tunable $Γ - K$ Valley Populations in Hole-Doped Trilayer ${WSe}_{2}$

Hema C. P. Movva, Timothy Lovorn, Babak Fallahazad, Stefano Larentis, Kyounghwan Kim, Takashi Taniguchi, Kenji Watanabe, Sanjay K. Banerjee, Allan H. MacDonald, and Emanuel Tutuc

Phys. Rev. Lett. 120, 107703 – Published 9 March 2018

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 $0.5 m_{e}$ and $1.2 m_{e}$ , 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.

Received 1 November 2017
Revised 7 January 2018

DOI:https://doi.org/10.1103/PhysRevLett.120.107703

Physics Subject Headings (PhySH)

Electronic structure Quantum Hall effect Valleytronics

2-dimensional systems Transition metal dichalcogenides

Band structure methods Density functional theory Shubnikov-de Haas effect k dot p method

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Hema C. P. Movva¹, Timothy Lovorn², Babak Fallahazad¹, Stefano Larentis¹, Kyounghwan Kim¹, Takashi Taniguchi³, Kenji Watanabe³, Sanjay K. Banerjee¹, Allan H. MacDonald², and Emanuel Tutuc^1,*

¹Microelectronics Research Center, Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA
²Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
³National Institute of Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan