Perfect valley polarization in MoS2

Abstract

We study perfect valley polarization in a molybdenum disulfide MoS2 nanoribbon monolayer using two bands Hamiltonian model and non-equilibrium Green's function method. The device consists of a one-dimensional quantum wire of MoS2 monolayer sandwiched between two zigzag MoS2 nanoribbons such that the sites A and B of the honeycomb lattice are constructed by the molecular orbital of Mo atoms, only. Spin-valley coupling is seen in energy dispersion curve due to the inversion asymmetry and time-reversal symmetry. Although, the time reversal symmetry is broken by applying an external magnetic field, the valley polarization is very small. A valley polarization equal to 46% can be achieved using an exchange field of 0.13 eV. It is shown that a particular spin-valley combination with perfect valley polarization can be selected based on a given set of exchange field and gate voltage as input parameters. Therefore, the valley polarization can be detected by detecting the spin degree of freedom.

References in corpus (6)

• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Aharonov-Bohm effect and broken valley-degeneracy in graphene rings
• Valley filter in strain engineered graphene
• Bound states and magnetic field-induced valley splitting in gate-tunable graphene quantum dots
• Valley Zeeman effect and spin-valley polarized conductance in monolayer MoS${}_2$ in a perpendicular magnetic field
• Intrinsic optical conductivity of modified-Dirac fermion systems

Cited by in corpus (2)

• Phase Transition and Field Effect Topological Quantum Transistor made of monolayer MoS2
• Spin polarization in Lateral two-dimensional Heterostructures