Gate-Voltage modulated spin caloritronics in Fe/Cr-doped Janus MoSeTe nanoribbons

Abstract

Conventional thermoelectric conversion based on charge transport faces significant challenges due to inherent limitations, such as a low power factor, inevitable Joule heating, and high thermal conductivity. To address these challenges, spin caloritronics offer a promising pathway for thermoelectric conversion based on the spin degree of freedom, which has attracted considerable interest because of its low energy consumption and high response speed. In this study, we systematically investigates the gate-voltage-tunable spin caloritronic properties of transition metal (Fe/Cr)-doped Janus MoSeTe nanoribbons through combined non-equilibrium Green's function and density functional theory. These results reveal that Cr-doped Janus MoSeTe devices demonstrate a perfect spin Seebeck effect with pure spin current under specific gate voltages. The Fe-doped system exhibits two negative differential thermal resistance peaks and achieves 100% thermal-driven spin polarization through effective spin filtering. Notably, both the magnitude and polarity of these negative differential thermal resistance peaks can be controlled via gate voltage, which is attributed to the fact that the gate voltage can modulate the spin-resolved transmission spectrum. Furthermore, these devices demonstrate a significant spin figure of merit (ZTsp,max∼ 42) near the Fermi level at T = 300 K. These findings highlight the potential for developing high-efficiency spin caloritronic devices and thermal management applications utilizing Fe/Cr-doped MoSeTe nanoribbons under a specific gate voltage.