Quantum metric non-linear Hall effect in an antiferromagnetic topological insulator thin-film EuSn2As2

TL;DR

This paper predicts a large, tunable non-linear Hall effect in antiferromagnetic topological insulator EuSn2As2 thin-films, driven by quantum metric effects, with potential applications in spintronics and electronic devices.

Contribution

It demonstrates the first prediction of a significant NLHE from quantum metric in EuSn2As2, highlighting a simple Dirac cone as the key mechanism and showing tunability via doping.

Findings

NLHE conductivity exceeds 20 mA/V2, surpassing previous reports.

Single Dirac cone provides a minimal model for NLHE.

Phosphorus doping doubles the non-linear Hall conductivity.

Abstract

The quantum geometric structure of electrons introduces fundamental insights into understanding quantum effects in materials. One notable manifestation is the non-linear Hall effect (NLHE), which has drawn considerable interest for its potential to overcome the intrinsic limitations of semiconductor diodes at low input power and high frequency. In this study, we investigate NLHE stemming from the real part of the quantum geometric tensor, specifically the quantum metric, in an antiferromagnetic topological material, EuSn2As2, using density functional theory. Our calculations predict a remarkable NLHE arising from a symmetry-protected, single Type-II surface Dirac cone in the even-numbered-layer two-dimensional slab thin-film, yielding a non-linear Hall conductivity exceeding 20 mA/V2-an order of magnitude larger than previously reported. This single Dirac band dispersion represents the simplest model for generating NLHE, positioning the EuSn2As2 thin-film as a hydrogen atom for NLHE systems. Additionally, we observe NLHE from band-edge states near the Fermi level. Our findings also reveal that 30% phosphorus (P) doping can double the non-linear Hall conductivity. With its substantial and tunable NLHE, EuSn2As2 thin-films present promising applications in antiferromagnetic spintronics and rectification devices.