Controlled giant magnetoresistance and spin–valley transport in an asymmetrical MoS2 tunnel junction

Abstract

We study the effects of asymmetrical magnetization and an optoelectronic tunable band structure on the transmission of particles in a MoS2 tunnel junction. Based on the results, we propose a model for a multifunctional coupler as a single system incorporating giant magnetoresistance, a spin–valley filter, and a spin–valley valve. The device is made up of ferromagnetic/ferromagnetic/normal junctions, with an off-resonant light and an electric gate potential functioning as the spin–valley filter and spin–valley valve, respectively. Increasing the asymmetrical magnetization is found to substantially enhance the tunneling magnetoresistance (TMR) of the system, leading to giant TMR. The spin–valley filtering is based on the spin imbalance modulation that arises from asymmetrical magnetization and the valley degeneracy breaking of off-resonant light, and the spin–valley valve is produced by altering the effective density of states of spin/valley polarized bands via the gate potential that controls the flow of spin/valley polarized particles. By fixing the magnetization configurations, one specific spin–valley filter and spin–valley valve can be acquired by tuning an external parameter to the corresponding spin/valley polarized energy windows.

Magnetoelectric tuning of spin, valley, and layer-resolved anomalous Nernst effect in transition-metal dichalcogenides bilayers

“…Here, we define q ± = ℏv f (ηq x ± i q y ) in which q x and q y are the perpendicular and parallel wave vectors, respectively. In equation (1), h refers to the energy contribution due to the exchange field which can be induced by the proximity effect using, e.g. BiFeO 3 [33,34] or EuO [35,36].…”

“….) are attracting considerable research [1][2][3][4][5] due to their direct band gap [6] and the inherently strong spin-orbit coupling (SOC) [7]. The former is due to the breaking of inversion symmetry, and the latter arises from the heavy metal's d orbitals locking the spin and valley degrees of freedom [8].…”

Perfect spin-valley polarization and magnetoresistance in MoS2 tunnel junction with circularly polarized light

“…5,21) The circularly polarized light (CPL) can break the valley degeneracy through the optical Stark effect. 22) Recently, some works on quantum transport properties by the off-resonance CPL have been reported in two-dimensional materials, such as graphene, [23][24][25] silicene, 26) MoS 2 , 27,28) WSe 2 [29][30][31] and so on. Tahir et al 27) theoretically analyzed the effective timeindependent Hamiltonian of MoS 2 with CPL based on Floquet theory which gives results in agreement with experiments, and discussed the influence of CPL on quantum spin and valley Hall effects.…”

“…In asymmetric F/F/N MoS 2 junction, the spin-valley filter and MR can be obtained by modulating the CPL. 28) The CPL-modulated double barrier WSe 2 junction can be manipulated as a valley filter and a valley valve. 30) A spin-valley dependent Klein tunneling and spin-and valley-polarized transport could be achieved by the CPL in a magnetic WSe 2 superlattice.…”

“…31) However, the works on MR controlled by the CPL are few. 28,29) In this paper, we proposed a new tunnel junction, i.e. the F/ CPL/F junction based on the monolayer MoS 2 , as shown in Fig.…”