Magnetic and electric control of spin- and valley-polarized transport across tunnel junctions on monolayer WSe2

M. Tahir, P. M. Krstajić, and P. Vasilopoulos
Phys. Rev. B 95, 235402 – Published 1 June 2017

Abstract

The recent experimental realization of high-quality WSe2 leads to the possibility of an efficient manipulation of its spin and valley degrees of freedom. Its electronic properties comprise a huge spin-orbit coupling, a direct band gap, and a strong anisotropic lifting of the degeneracy of the valley degree of freedom in a magnetic field. We evaluate its band structure and study ballistic electron transport through single and double junctions (or barriers) on monolayer WSe2 in the presence of spin Ms and valley Mv Zeeman fields and of an electric potential U. The conductance versus the field Ms or Mv decreases in a fluctuating manner. For a single junction, the spin Ps and valley Pv polarizations rise with M=Mv=2Ms, reach a value of more than 55%, and become perfect above U45 meV while for a double junction this change can occur for U50 meV and M5 meV. In certain regions of the (M,U) plane Pv becomes perfect. The conductance gc, its spin-up and spin-down components, and both polarizations oscillate with the barrier width d. The ability to isolate various carrier degrees of freedom in WSe2 may render it a promising candidate for new spintronic and valleytronic devices.

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  • Received 25 March 2017

DOI:https://doi.org/10.1103/PhysRevB.95.235402

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

M. Tahir1,*, P. M. Krstajić2,†, and P. Vasilopoulos3,‡

  • 1Department of Physics, College of Science, University of Hafr Al Batin, P.O. Box 1803, Hafr Al Batin 31991, Kingdom of Saudi Arabia
  • 2Center of Microelectronic Technologies and Single Crystals (IHTM), University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia
  • 3Department of Physics, Concordia University, 7141 Sherbrooke West, Montreal, Quebec, Canada H4B 1R6

  • *m.tahir06@alumni.imperial.ac.uk
  • predrag222@gmail.com
  • p.vasilopoulos@concordia.ca

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Issue

Vol. 95, Iss. 23 — 15 June 2017

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