Semiconducting ${\alpha'}$-borophene nanoribbon for high-efficiency spin-Seebeck diodes

Abstract

The semiconductiong ${\alpha'}$-borophene nanoribbon (${\alpha'}$-BNR) due to its incredible properties such as high stability and great mobility of carriers demostrates high-efficiency in thermoelectric devices. These properties enable us to produce the spin current by a temperature gradient with lower energy consumption technology. In this research, the spin-dependent Seebeck effects are studied in a zigzag ${\alpha'}$-borophene nanoribbon with two leads magnetized by ferromagnetic (FM) insulators. The thermoelectric calculations are performed for a ${\alpha'}$-BNR FM/Normal/FM junction using the tight-binding (TB) formalism in combination with the non-equilibrium Green's function method (NEGF). A pure spin-dependent current due to the breaking of the electron-hole symmetry is induced in the system by a temperature gradient so that it can act as a spin-Seebeck diode. Moreover, the negative differential spin-Seebeck effect can be observed in this device dueto the compensation of thermal spin in the spin-dependent currents. Finally, we have studied the effect of temperature on the charge and spin power factors in ${\alpha'}$-BNR. A significant decline in power factor is primarily arises from a reduction in the magnitude of thermopower near the Fermi level. Our findings demonstrate that the ${\alpha'}$-BNR has a higher power factor compared to its rivals e.g., graphene and silicene. This is attributed to the semiconducting nature and high asymmetry between electrons and holes in the ${\alpha'}$-BNR. The exceptional features of ${\alpha'}$-BNR makes it a very suitable choice for using in thermoelectric devices.