Valley- and spin-filter in monolayer MoS$_2$

TL;DR

This paper proposes a tunable valley- and spin-filter device using a MoS₂ junction, where polarizations can be controlled via gate voltage and exchange field, with conductance affected by a topological term.

Contribution

It introduces a novel MoS₂-based valley- and spin-filter with tunable polarization and conductance properties using a modified Dirac Hamiltonian and scattering formalism.

Findings

Polarizations can be inverted by reversing the exchange field.

Gate voltage and exchange field tune the polarizations.

Topological term affects charge conductance depending on exchange field.

Abstract

We propose a valley- and spin-filter based on a normal/ferromagnetic/normal molybdenum disulfide (MoS$_2$) junction where the polarizations of the valley and the spin can be inverted by reversing the direction of the exchange field in the ferromagnetic region. By using a modified Dirac Hamiltonian and the scattering formalism, we find that the polarizations can be tuned by applying a gate voltage and changing the exchange field in the structure. We further demonstrate that the presence of a topological term ($\beta$) in the Hamiltonian results in an enhancement or a reduction of the charge conductance depending on the value of the exchange field.