Thermal spin-Edelstein effect in an antiferromagnetic insulator/normal metal heterostructure

In an antiferromagnetic insulator with biaxial anisotropy and the Dzyaloshinskii-Moriya interaction (DMI), symmetry ensures a spin-momentum locking similar to that of gapped Rashba electrons. A temperature gradient can generate an interfacial magnon accumulation with a preferred spin polarization, realizing the magnonic counterpart of the spin Edelstein effect. This thermally-driven magnonic spin accumulation can be injected into an adjacent heavy metal and converted into a measurable voltage, which depends monotonically on both temperature and DMI but non-monotonically on the surface-induced magnetic anisotropy. It is found that the overall response coefficient has to be solved under a nontrivial boundary condition regarding spin transmission across the interface.