Spin and valley polarization transport of monolayer MoS2 field-effect transistors modulated by optically controlled source and drain
Due to the unique spin and valley electronic properties of new two-dimensional materials,it has become the key material for the preparation of quantum integrated devices.Optical modulation is an effective method to change the properties of two-dimensional materials.In recent years,the use of circularly polarized light to manipulate valley degrees of freedom has attracted a lot of attention.In this study,based on Floquet scattering theory and transfer matrix method,spin-and valley-polarized transport in monolayer MoS2 field-effect transistor(FET)with optically controlled source and drain have been investigated theoretically.The results show that,compared with light irradiated on gate,the spin-and valley-polarized transport exhibits greater sensitivity to the gate voltage when the source and drain are applied with light field.Especially,the polarized transport dominated by K valley can be transformed into a K valley filtering effect by adjusting the gate direction.More interestingly,in this structure,the 100％valley polarization is almost independent of the size of the quantum structure when the electrons are incident with low energy.These new findings provide potential applications for the development of novel transition metal dichalcogenide FETs.
spin-and valley-polarized transportcircularly polarized lightMoS2 field effect transistor
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