Intrinsic Magnon Nernst Effect in Pyrochlore Iridate Thin Films

We theoretically study the intrinsic magnon Nernst effect in pyrochlore iridate trilayer thin films grown along the [111] direction using a strong coupling approach. The spin configuration of the ground state is the all-in–all-out (AIAO) state resulted from the Dzyaloshinskii-Moriya interaction. In such a state, the system has an inversion symmetry and a conserved spin current is well defined. We then calculate the magnon Nernst response with respect to the lowest magnon band Chern number controlled by the spin-orbit coupling parameters. Our study complements prior work in the magnon thermal Hall effect of thin-film pyrochlore iridates and suggests that the [111] grown thin-film pyrochlore iridates are a promising candidate for thermal spin transport and caloritronic devices.