Generation of large spin and valley currents in a quantum pump based on molybdenum disulfide
Generation of large currents, versatile functionality, and simple structure are of fundamental importance in development of adiabatic quantum pump devices with nanoscale dimensions. In the present study, we propose an adiabatic quantum pump with simple structure based on molybdenum disulfide, MoS2, to generate large spin and valley resolved currents. We show that pure and fully polarized spin and valley currents can be easily generated by employing two potential gates and using an exchange magnetic field. Unlike graphene and silicene, to induce valley resolved current in MoS2, one does not need to induce strain and apply electric field. The spin and valley resolved currents are completely coupled together, so that the spin up (down) current is exactly the valley K(K0) current. Hence, we can detect the valley resolved current by utilizing more straightforward and simple methods used for detection of spin resolved current. The other prominent feature of this proposed pump is its large current, which is two and three orders of magnitude larger than the maximum current of similar pump structures based on silicene and graphene resepectively. The results of this study are promising for fabrication of quantum pumps with large spin and valley resolved currents, which opens up the possibility for further development of spintronics and valleytronics in 2D nanostructures.