Giant spin Seebeck effect in two-dimensional V2S2O altermagnet

Altermagnet is an uncommon category of antiferromagnets distinguished by their non-overlapping spin-bands, drawing significant attention from researchers. However, while reports on their electronic and magnetic properties are increasing rapidly, the study on the transport properties is still in early stage. Therefore, we explored the orientational spin-dependent transport features of altermagnet V2S2O using Boltzmann transport technique. This altermagnet had 1.15 eV direct band gap energy and a critical temperature of 746 K. We obtained a directional spin-dependent feature in the band structure whose effect spans through all the spin-dependent transport parameters. We found a low isotropic lattice thermal conductivity of magnitude 0.2 Wm-1K-1 at 300 K. Above all, the V2S2O altermagnet displayed a giant spin-dependent Seebeck coefficient of about 1.8 mVK-1 at 300 K and at a small electron or hole doping. This value is multiple times greater than reported values for most transport materials. Besides, we also found a maximum figure of merit of 0.86 in the hole-doped systems. Thus, our findings suggest the possibility of pure spin current generation for possible applications in spintronics and thermoelectricity.