Valley-controlled transport in graphene/ WSe${}_2$ heterostructures under an off-resonant polarized light

Abstract

We investigate the electronic dispersion and transport properties of graphene/WSe${}_2$ heterostructures in the presence of a proximity-induced spin-orbit coupling ${\lambda }_v$, sublattice potential $\Delta$, and an off-resonant circularly polarized light of frequency $\Omega$ that renormalizes $\Delta$ to ${\bar{\Delta }}_{\eta p}=\Delta +\eta p{\Delta }_{\Omega }$ with $\eta$ and $p$ the valley and polarization indices, respectively, and ${\Delta }_{\Omega }$ the gap due to the off-resonant circularly polarized light. Using a low-energy Hamiltonian we find that the interplay between different perturbation terms leads to inverted spin-orbit coupled bands. At high $\Omega$ we study the band structure and dc transport using the Floquet theory and linear response formalism, respectively. We find that the inverted band structure transfers into the direct band one when the off-resonant light is present. The valley-Hall conductivity behaves as an even function of the Fermi energy in the presence and absence of this light. At ${\Delta }_{\Omega }$ = ${\lambda }_v$ - $\Delta$ a transition occurs from the valley-Hall phase to the anomalous Hall phase. In addition, the valley-Hall conductivity switches sign when the polarization of the off-resonant light changes. The valley polarization vanishes for ${\Delta }_{\Omega }$ = 0 but it is finite for ${\Delta }_{\Omega }$ $\ne$ 0 and reflects the lifting of the valley degeneracy of the energy levels, for ${\Delta }_{\Omega }\ne 0$, when the off-resonant light is present. The corresponding spin polarization, present for ${\Delta }_{\Omega }$ = 0, increases for ${\Delta }_{\Omega }$ $\ne$ 0. Further, pure $K$ or $K^{\prime }$ valley polarization is generated when ${\Delta }_{\Omega }$ changes sign. Also, the charge Hall conductivity is finite for ${\Delta }_{\Omega }\ne 0$ and changes sign when the handedness of the light polarization changes.

References in corpus (21)

• The electronic properties of graphene
• Valley filter and valley valve in graphene
• Photovoltaic Hall effect in graphene
• Spin-Orbit Proximity Effect in Graphene
• Irradiated graphene as a tunable Floquet topological insulator
• Multiterminal Conductance of a Floquet Topological Insulator
• Effective Theory of Floquet Topological Transitions
• Large Proximity-Induced Spin Lifetime Anisotropy in Transition Metal Dichalcogenide/Graphene Heterostructures
• Dissipative Floquet Topological Systems
• Microscopic theory for the light-induced anomalous Hall effect in graphene
• Optical conductivity of bilayer graphene with and without an asymmetry gap
• Colossal negative magnetoresistance in dilute fluorinated graphene
• Tunable spin-orbit coupling and symmetry-protected edge states in graphene/WS${}_2$
• Optimal charge-to-spin conversion in graphene on transition metal dichalcogenides
• Occupation of topological Floquet bands in open systems
• Magnetotransport in heterostructures of transition metal dichalcogenides and graphene
• Graphene-WS${}_2$ heterostructures for tunable spin injection and spin transport
• Photoinduced quantum spin and valley Hall effects and orbital magnetization in monolayer MoS2
• Enhanced electron-phonon coupling in graphene with periodically distorted lattice
• Absence of a transport signature of spin-orbit coupling in graphene with indium adatoms
• Off-resonant polarized light-controlled thermoelectric transport in ultrathin topological insulators

Cited by in corpus (2)

• Off-resonant light-induced topological phase transition and thermoelectric transport in semi-Dirac materials
• Phase transition from Weyl to self-linked semimetal using bi-circular laser