Thermal currents obtained and mutually switched by a modified Haldane model in graphene

Abstract

By using the transfer matrix method, we discover three types of current, such as the 100% spin-valley polarized current, pure spin-valley current and pure charge current, in a two-terminal graphene system. These types of current can be obtained and mutually switched by modulating the parameters of the modified Haldane model (MHM). In our work, these types of current are driven by the thermal bias. Compared with this method of increasing the one-lead temperature (with a fixed temperature difference), the thermal currents can be more effectively strengthened by increasing the temperature difference (with a fixed one-lead temperature). In order to rapidly turn off these currents, we choose to enhance the intensity of the off-resonant circularly polarized light instead of canceling the temperature difference. These results indicate that the graphene system with the MHM has promising applications in the spin and valley caloritronics.