Magneto-optical transport properties of monolayer WSe2

TL;DR

This paper investigates the magneto-optical transport properties of monolayer WSe2, emphasizing the effects of strong spin-orbit coupling and valley pseudospin splitting on its optical and Hall conductivities under magnetic fields.

Contribution

It provides a detailed theoretical analysis of WSe2's energy spectrum and magneto-optical responses, highlighting tunable spin and valley splittings in different frequency regimes.

Findings

Magneto-optical conductivities are strongly affected by magnetic field and spin splitting.

Valley polarization and oscillation beatings are observed in the Hall conductivity.

Magneto-optical responses can be tuned across microwave, terahertz, and visible frequency regimes.

Abstract

The recent experimental realization of a high quality WSe$% _{2} $ leads to the possibility of magneto-optical measurements and the manipulation of the spin and valley degrees of freedom. We study the influence of the very strong spin-orbit coupling and of the anisotropic lifting of the valley pseudospin degeneracy on its magnetotransport properties. The energy spectrum of WSe$_{2} $ is derived and discussed in the presence of a perpendicular magnetic field $B$. Correspondingly we evaluate the magneto-optical Hall conductivity and the optical longitudinal conductivity as functions of the frequency, magnetic field, and Fermi energy. They are strongly influenced by the field $B$ and the strong spin splitting. The former exhibits valley polarization and the latter beatings of oscillations. The magneto-optical responses can be tuned in two different regimes: the mictrowave-to-terahertz regime and the visible-frequency one. The absorption peaks involving the $n=0$ LL appear in between these two regimes and show a magnetic control of the spin and valley splittings. We also evaluate the power absorption spectrum.