Spin transport inn-type single-layer transition-metal dichalcogenides

Abstract

Valley asymmetry of the electron spectrum in transition metal dichalcogenides (TMDs) originates from the spin-orbit coupling. Presence of spin-orbit fields of opposite signs for electrons in K and K valleys in combination with possibility of intervalley scattering result in a nontrivial spin dynamics. This dynamics is reflected in the dependence of nonlocal resistance on external magnetic field (the Hanle curve). We calculate theoretically the Hanle shape in TMDs. It appears that, unlike conventional materials without valley asymmetry, the Hanle shape in TMDs is different for normal and parallel orientations of the external field. For normal orientation, it has two peaks for slow intervalley scattering, while for fast intervalley scattering, the shape is usual. For parallel orientation, the Hanle curve exhibits a cusp at zero field. This cusp is a signature of a slow-decaying valley-asymmetric mode of the spin dynamics.

Signature of Hanle precession in trilayer MoS2 : Theory and experiment

“…As a result of averaging out of ±B SO the − mode has a long lifetime, ∼ Ω form of S x (t) in the domain Γ > 1 is still the sum of the products of oscillating and exponentially decaying functions, as we have demonstrated in Ref. [42]. This allows to calculate the Hanle curve explicitly for finite separation, d, between the contacts.…”

“…In our earlier paper Ref. [42] we have demonstrated that the analytical solution of the system depends on the dimensionless ratio…”

“…In Ref. [42] we considered the case d λ s . With regard to our present experimental study, the opposite limit d λ s is relevant.…”

“…If the mobility is limited entirely by the intervalley scattering, it is related to γ v and the carrier density n as [42]:…”

“…To compare these results with theory, we have also extended our previous theoretical work Ref. [42] to incorporate the case of a finite distance between injector and detector.…”