Intrinsic nonlinear Nernst and Seebeck effect

TL;DR

This paper uncovers intrinsic nonlinear Nernst and Seebeck effects driven by band geometry in antiferromagnets, independent of scattering, advancing thermoelectric energy harvesting research.

Contribution

It reveals the intrinsic scattering-free nonlinear thermoelectric currents originating from Berry connection polarizability in bipartite antiferromagnets, demonstrated through CuMnAs.

Findings

Intrinsic nonlinear Nernst and Seebeck currents dominate over scattering-dependent effects.

These currents originate from Berry connection polarizability tensor.

The results deepen understanding of nonlinear thermoelectric phenomena.

Abstract

The Nernst and Seebeck effects are crucial for thermoelectric energy harvesting. However, the linear anomalous Nernst effect requires magnetic materials with intrinsically broken time-reversal symmetry. In non-magnetic systems, the dominant transverse thermoelectric response is the nonlinear Nernst current. Here, we investigate nonlinear Nernst and Seebeck effects to reveal intrinsic scattering-free Seebeck and Nernst currents arising from band geometric effects in bipartite antiferromagnets (parity-time-reversal symmetric systems). We show that these contributions, independent of scattering time, originate from the Berry connection polarizability tensor which depends on the quantum metric. Using CuMnAs as a model system, we demonstrate the dominance of intrinsic nonlinear Seebeck and Nernst currents over other scattering-dependent contributions. Our findings deepen the fundamental understanding of nonlinear thermoelectric phenomena and provide the foundation for using them to develop more efficient, next-generation energy harvesting devices.