Zeeman- and electric-field control of spin- and valley-polarized transport through biased magnetic junctions on WSe2

Abstract

The electronic properties of WSe2 comprise a huge spin-orbit coupling, a wide direct band gap, and especially a strong anisotropic lifting of the degeneracy of the valley degree of freedom in a magnetic field. We study ballistic electron transport through single or double junctions on monolayer WSe2 in the presence of spin M-s and valley M-v Zeeman fields and of an electric potential U. The conductance vs. the field M-s or M-v decreases in a fluctuating manner. For a single junction the spin P-s and valley P-v polarizations rise with M = M-v = 2M(s), reach a value of more than 70%, and become perfect above U approximate to 90meV while for a double junction this change can occur for U approximate to 50meV and M >= 10meV. Pv increases with U and both polarizations oscillate with the junction width. The results may render WSe2 a promising candidate for new spintronic and valleytronic devices.