Giant spin Seebeck in semiconducting ferromagnetic Ga0.5V0.5As

Abstract

The spin Seebeck effect (SSE) represents one of the most essential features in the field of spin caloritronics. The generation of spin current in magnetic materials based on temperature gradient is referred to as the SSE. However, a low SSE in most magnetic materials poses a setback to potential device applications. Hence, a search for new magnetic materials with a giant SSE becomes fundamental and time sensitive. So, we investigate the directional spin-dependent transport features of bulk Ga_0.5V_0.5As ferromagnetic semiconductor using the Boltzmann transport method. The spin-dependent electronic thermal conductivity (k^↑ and k^↓) and electrical conductivity (σ^↑ and σ^↓) obtained were higher along the perpendicular channel. We found a giant effective SSE of magnitude 1469 μVK^-1 along the perpendicular channel and 1440 μVK^-1 along the in-plane channel in the n-type systems. These values are several times larger than in most other bulk systems. Overall, we obtained higher ZT values in the perpendicular channel. Our calculated spin and charge ZT values of 0.59 and 0.63 are about 50 times higher than the ZT of bulk non-magnetic, pristine GaAs. Thus, our findings may serve as baseline data for further experimental studies on energy applications in the field of spin caloritronics.