Intrinsic Nonlinear Planar Thermal Hall Effect

TL;DR

This paper introduces the intrinsic nonlinear planar thermal Hall effect, a dissipationless thermal response driven by quantum geometry, which depends on the Berry curvature correction and is controllable via angular dependence in noncentrosymmetric materials.

Contribution

The paper reveals a new intrinsic nonlinear thermal Hall effect originating from quantum geometry, characterized by the thermal Berry connection polarizability tensor, and demonstrates its symmetry conditions and controllability.

Findings

The effect is dissipationless and independent of scattering time.

It occurs only in noncentrosymmetric crystals lacking horizontal mirror symmetry.

Angular dependence allows control over the nonlinear thermal response.

Abstract

We introduce the intrinsic nonlinear planar thermal Hall effect (NPTHE)-- a dissipationless thermal response proportional to $(\nabla T)^2B$, which arises when the temperature gradient $\nabla T$ and magnetic field $\mathbf{B}$ lie within the same plane. The effect originates from a thermal gradient induced correction to the Berry curvature, characterized by the thermal Berry connection polarizability (TBCP) tensor, leading to a nonlinear transverse heat current independent of scattering time. A symmetry analysis shows that the intrinsic NPTHE is permitted only in noncentrosymmetric crystal point groups lacking horizontal mirror symmetry. Using a tilted Dirac model, we demonstrate that its characteristic angular dependence provides an effective means to control the nonlinear thermal response. Our results establish a new class of quantum geometry driven intrinsic nonlinear thermal transport, offering both a sensitive probe of band geometry and a pathway toward nonlinear thermal functionalities in quantum materials.