Novel valley depolarization dynamics and valley Hall effect of exciton in mono- and bilayer MoS${}_2$

Abstract

We investigate the valley depolarization dynamics and valley Hall effect of exciton due to the electron-hole exchange interaction in mono- and bilayer MoS${}_2$ by solving the kinetic spin Bloch equations. The effect of the exciton energy spectra by the electron-hole exchange interaction is explicitly considered. For the valley depolarization dynamics, in the monolayer MoS${}_2$, it is found that in the strong scattering regime, the conventional motional narrowing picture is no longer valid, and a novel valley depolarization channel is opened. For the valley Hall effect of exciton, in both the mono- and bilayer MoS${}_2$, with the exciton equally pumped in the K and K' valleys, the system can evolve into the equilibrium state where the valley polarization is parallel to the effective magnetic field due to the exchange interaction. With the drift of this equilibrium state by applied uniaxial strain, the exchange interaction can induce the {\it momentum-dependent} valley/photoluminesence polarization, which leads to the valley/photoluminesence Hall current. Specifically, the disorder strength dependence of the valley Hall conductivity is revealed. In the strong scattering regime, the valley Hall conductivity decreases with the increase of the disorder strength; whereas in the weak scattering regime, it saturates to a constant, which can be much larger than the one in Fermi system due to the absence of the Pauli blocking.

14 pages, 7 figures

References in corpus (27)

• Valley polarization in MoS2 monolayers by optical pumping
• The Valley Hall Effect in MoS2 Transistors
• Exciton Binding Energy of Monolayer WS2
• Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
• Spin current and polarization in impure 2D electron systems with spin-orbit coupling
• Robust optical emission polarization in MoS2 monolayers through selective valley excitation
• Semiclassical theories of the anomalous Hall effect
• Valley excitons in two-dimensional semiconductors
• Exciton band structure of monolayer MoS2
• Exciton Valley Dynamics probed by Kerr Rotation in WSe2 Monolayers
• Nonanalyticity, Valley Quantum Phases, and Light-like Exciton Dispersion in Monolayer TMDs: Theory and First-Principles Calculations
• Polarization and time-resolved photoluminescence spectroscopy of excitons in MoSe2 monolayers
• Spin and valley dynamics of excitons in transition metal dichalcogenides monolayers
• Absence of vertex correction for the spin Hall effect in p-type semiconductors
• Berry Phase Effect on Exciton Transport and Bose Einstein Condensate
• Exciton dynamics in WSe2 bilayers
• Effect of interface disorder on quantum well excitons and microcavity polaritons
• Theory of coupled spin-charge transport due to spin-orbit interaction in inhomogeneous two-dimensional electron liquids
• Exciton-polaritons in transition-metal dichalcogenides and their direct excitation via energy transfer
• Electron spin diffusion and transport in graphene
• Valley Hall effect in disordered monolayer MoS2 from first principles
• Vanishing spin-Hall current in a diffusive Rashba two-dimensional electron system: A quantum Boltzmann equation approach
• Spin relaxation under identical Dresselhaus and Rashba coupling strengths in GaAs quantum wells
• Spin Hall Effect of Excitons
• Electron spin diffusion in monolayer MoS${}_2$
• Hole spin relaxation in bilayer WSe${}_2$
• Theory optical excitation spectra and depolarization dynamics in bilayer WS${}_2$ from viewpoint of excimers

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• Topological Ising pairing states in monolayer and trilayer TaS${}_2$
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• A novel superconducting-velocity--tunable quasiparticle state and spin relaxation in GaAs (100) quantum wells in proximity to $s$-wave superconductor
• Unveiling the multi-level structure of midgap states in Sb-doped MoX${}_2$ (X = S, Se, Te) monolayers
• Inheritance of the exciton geometric structure from Bloch electrons in two-dimensional layered semiconductors
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• Valley Emission and Upconversion in Isotopically Engineered Monolayer WS${}_2$ under Resonant Excitation
• Room temperature interlayer exciton valley polarization and valley Hall effect