Probing valley quantum oscillations via the spin Seebeck effect in transition metal dichalcogenide/ferromagnet hybrids

TL;DR

This paper theoretically explores how spin-valley coupling and magnetic fields in transition metal dichalcogenide/ferromagnet heterostructures produce valley-polarized spin currents with quantum oscillations, revealing signatures of quantized valley states.

Contribution

It introduces a theoretical framework for detecting valley quantum oscillations via the spin Seebeck effect in heterostructures, highlighting the role of spin-valley coupling and magnetic fields.

Findings

Prediction of quantum oscillations in valley-polarized spin current

Identification of distinct microscopic origins for spin and valley-polarized currents

Proposal of experimental signatures for quantized valley states

Abstract

We theoretically investigate spin-valley-locked tunneling transport in a transition-metal dichalcogenide/ferromagnetic-insulator heterostructure under a perpendicular magnetic field, driven by the spin Seebeck effect. We demonstrate that spin-valley coupling together with the magnetic-field-induced valley-asymmetric Landau-level structure enables the generation of a valley-polarized spin current from valley-selective spin excitation. We compare the spin current and the valley-polarized spin current in the conduction and valence bands and clarify their distinct microscopic origins. We predict pronounced quantum oscillations of the valley-polarized spin current, providing a clear experimental signature of quantized valley states.