Linear thermal noise induced by Berry curvature dipole in a four-terminal system

TL;DR

This paper numerically studies linear thermal noise in a four-terminal system with Berry curvature dipole, revealing how noise correlates with BCD orientation, temperature, and dephasing effects, bridging bulk and quantum transport theories.

Contribution

It establishes a connection between semiclassical bulk results and quantum multi-terminal noise, highlighting symmetry and geometry effects in thermal noise due to Berry curvature dipole.

Findings

Auto-correlation scales as 2k_B T when perpendicular to BCD

Cross-correlation scales as k_B T and peaks near band edges

Thermal noise increases linearly with T at low T and is suppressed at high T

Abstract

In this work, we numerically investigate linear thermal noise in a four-terminal system with a finite Berry curvature dipole (BCD) using the nonequilibrium Green's function formalism. By comparing with the semiclassical results for bulk systems, we establish a one-to-one correspondence between terminal-resolved linear noise in multi-terminal systems and direction-resolved noise in bulk transport. Specifically, the auto-correlation function scales as $2 k_B T$ when the driving field is perpendicular to the BCD and vanishes when they are parallel, whereas the cross-correlation scales as $k_B T$. Both the auto- and cross-correlation functions exhibit pronounced peaks near the band edges, consistent with BCD-induced features. In addition, the linear thermal noise increases approximately linearly with $T$ at low temperatures and is suppressed by dephasing effect at high temperatures. Our work bridges semiclassical bulk theory and quantum multi-terminal theory for linear thermal noise, highlighting the symmetry(geometry)-selection rule in quantum transport.