Layer Nernst and thermal Hall effects in two-dimensional antiferromagnets

In two-dimensional (2D) layered materials, the layer acts as a crucial degree of freedom, enabling the emergence of exotic physical phenomena through its coupling with charge and spin. Here, using first-principles calculations and group theory analysis, we reveal that layer Nernst and layer thermal Hall effects are present in various 2D A-type layered antiferromagnets, including the metal Hf2S, the normal insulator CrI3, and the topological insulator MnBi2Te4. The application of an out-of-plane electric field removes the key magnetic group symmetries and breaks the spin degeneracy of the electronic structures in these 2D antiferromagnets. This spin splitting induces an imbalanced distribution of Berry curvature between the top and bottom layers. By quantitatively calculating the layer-resolved Nernst and thermal Hall conductivities, we confirm the existence of nonzero transverse charge and heat currents in response to a longitudinal temperature gradient field. The calculated conductivities are comparable to, or might even exceed, those of previously well-known altermagnets and noncollinear antiferromagnets that exhibit anomalous Nernst and thermal Hall effects. Our findings provide deeper insights into the thermal transport properties of 2D layered antiferromagnets and pave the way for future developments in antiferromagnetic spintronics, spin caloritronics, and layertronics.