Edge passivation oxidation-enhanced spin caloritronics in zigzag blue phosphorus nanoribbons

Abstract

Abstract In this study, the spin caloritronics of zigzag blue phosphorus nanoribbons (ZBPNRs) with edge hydrogenation and oxidation were studied using first-principles calculations and the non-equilibrium Green’s function method. Three different cases were considered: two edges of the ZBPNR were oxidized (2O-ZBPNR) and hydrogenated (2H-ZBPNR), one edge was oxidized, and the other was hydrogenated (HO-ZBPNR). Our results show that a perfect thermal spin filtering effect (SFE) and a negative differential thermoelectric resistance (NDTR) can be observed in structures with both 2O-ZBPNR and HO-ZBPNR, whereas these features were not found for 2H-ZBPNR. Furthermore, we confirmed that edge oxygen atoms in ZBPNRs offer different transport pathways for spin-up and spin-down states, leading to thermal SFE, and devices with oxygen-passivated ZBPNRs exhibited strong spin figures of merit (∼38) and large spin Seebeck coefficients (∼9 mV K−1).