Abstract
We theoretically study the magneto-optical transport properties of monolayer molybdenum disulfide (${\mathrm{MoS}}_{2}$) 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 ${\mathrm{MoS}}_{2}$ 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 ${\mathrm{SiO}}_{2}$ 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 Fr\"ohlich interaction. The dependence of the MOAC and FWHM on temperature, magnetic field, and the effective ${\mathrm{MoS}}_{2}$-substrate distance is also examined. The present results for monolayer ${\mathrm{MoS}}_{2}$ 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 ${\mathrm{MoS}}_{2}$, which could be further experimentally and theoretically investigated in the future.
Highlights
In parallel with the rise of graphene and the discovery of its outstanding electronic properties as well as the use of this material in applications [1,2,3], the focus has been shifting to the other two-dimensional (2D) transition-metal dichalcogenides with promising electronic properties and potential applications [4,5,6]
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 MoS2 acoustic, optical phonons, and the surface optical (SO) phonons induced by polar substrates
In specific terms of PE coupling, the contribution of TA phonons is about 1.6 times larger than that of longitudinal acoustic (LA) phonons, which can result from smaller TA phonon velocity when the MOAC is nearly proportional to vs−λ2 [see Eq (25)], agreeing with the previous work [39]
Summary
In parallel with the rise of graphene and the discovery of its outstanding electronic properties as well as the use of this material in applications [1,2,3], the focus has been shifting to the other two-dimensional (2D) transition-metal dichalcogenides with promising electronic properties and potential applications [4,5,6]. It has been demonstrated that monolayer MoS2 has a large carrier mobility [13], high thermal stability, good compatibility with standard semiconductor manufacturing [5], and high current carrying capacity [14]. These properties make MoS2 a promising alternative to graphene and have made it a candidate for a wide range of applications such as field-effect transistors [5,15], valleytronics devices [6,16,17,18], spintronic devices [19], and photonics [20]. Its electronic and band structure can be obtained from the k · p theory framework [9], the continuum theory [22], or from the more
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