Magneto-optical transport properties of monolayer MoS2 on polar substrates

Abstract

We theoretically study the magneto-optical transport properties of monolayer molybdenum disulfide (MoS_2) on polar substrates in the presence of a perpendicular magnetic field. The magneto-optical absorption coefficient (MOAC) is investigated as a function of the incident photon energy when carriers are scattered by three different types of phonons: the intrinsic MoS_2 acoustic, optical phonons, and the surface optical (SO) phonons induced by polar substrates. Among the substrates considered, the largest magnitude of MOAC and full-width at half maximum (FWHM) are observed for a SiO_2 substrate over the entire temperature and magnetic field range considered due to its strongest electron-SO phonon scattering, while an h-BN substrate displays the lowest one. The piezoelectric (PE) coupling to the transverse (TA) phonon is shown to dominate the MOAC and FWHM due to intrinsic acoustic phonon scattering. Meanwhile, these properties for intrinsic optical phonons are dominated by zero-order deformation potential (DP) couplings and the Fröhlich interaction. The dependence of the MOAC and FWHM on temperature, magnetic field, and the effective MoS_2-substrate distance is also examined. The present results for monolayer MoS_2 are compared with those in conventional two-dimensional systems as well as in graphene. Our results show that SO phonons play a crucial role at high temperature depending on the substrates and have a non-negligible effect on the magneto-optical transport properties of monolayer MoS_2, which could be further experimentally and theoretically investigated in the future.