Nonlinear valley and spin currents from Fermi pocket anisotropy in 2D crystals

Abstract

Controlled flow of spin and valley pseudospin is key to future electronics exploiting these internal degrees of freedom of carriers. Here we discover a universal possibility for generating spin and valley currents by electric bias or temperature gradient only, which arises from the anisotropy of Fermi pockets in crystalline solids. We find spin and valley currents to the second order in the electric field, as well as their thermoelectric counterparts, i.e. the nonlinear spin and valley Seebeck effects. These second-order nonlinear responses allow two unprecedented possibilities to generate pure spin and valley flows without net charge current: (i) by an AC bias; or (ii) by an arbitrary inhomogeneous temperature distribution. As examples, we predict appreciable nonlinear spin and valley currents in two-dimensional (2D) crystals including graphene, monolayer and trilayer transition metal dichalcogenides, and monolayer gallium selenide. Our finding points to a new route towards electrical and thermal generations of spin and valley currents for spintronic and valleytronic applications based on 2D quantum materials.

References in corpus (13)

• Two Dimensional Atomic Crystals
• Valley polarization in MoS2 monolayers by optical pumping
• Dissipationless Quantum Spin Current at Room Temperature
• The Valley Hall Effect in MoS2 Transistors
• High Performance Single Layered WSe2 p-FETs with Chemically Doped Contacts
• Valley filter and valley valve in graphene
• Valley Dependent Optoelectronics from Inversion Symmetry Breaking
• Theory of magnon-driven spin Seebeck effect
• Generation and Electric Control of Spin-Coupled Valley Current in WSe2
• Giant Nonlocality near the Dirac Point in Graphene
• Generation of pure bulk valley current in graphene
• Quantized conductance in an AlAs 2D electron system quantum point contact
• Spin Relaxation in Single Layer Graphene with Tunable Mobility

Cited by in corpus (13)

• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Valley Polarization by Spin Injection in a Light-Emitting van der Waals Heterojunction
• Optical response of monolayer, few-layer and bulk tungsten disulfide
• Nonlinear spin current generation in noncentrosymmetric spin-orbit coupled systems
• Valley Acoustoelectric Effect
• Optical generation and detection of pure valley current in monolayer transition metal dichalcogenides
• Discrete solitons in graphene metamaterials
• Valley filtering effect of phonons in graphene with a grain boundary
• Role of Berry curvature in the generation of spin currents in Rashba systems
• Theory of Nonlinear Response for Charge and Spin Currents
• Spin supercurrent in superconductor/ferromagnet van-der-Waals heterostructures
• Nonlinear Valley and Spin Valves in Bilayer Graphene
• Scalable multicomponent spectral analysis for high-throughput data annotation