Anisotropic anomalous Hall effect in distorted kagome GdTi3Bi4

TL;DR

This study reveals an orientation-dependent anomalous Hall effect in GdTi3Bi4, where the Hall conductivity varies with magnetic field direction due to orbital effects, highlighting complex magnetic-electronic interactions in kagome magnets.

Contribution

It demonstrates the control of anomalous Hall conductivity by magnetization direction in GdTi3Bi4, combining experimental transport measurements with first principles calculations.

Findings

Anomalous Hall conductivity of 410 S/cm at 2 K for B//c

Absence of AHE for B//a despite similar magnetization

Orbital mixing and Berry curvature hot spots depend on magnetization orientation

Abstract

Topological kagome magnets offer a rich landscape for exploring the intricate interplay of quantum interactions among geometry, topology, spin, and correlation. GdTi3Bi4 crystallizes in layered Ti based kagome nets intertwined with zigzag Gd chains along the a axis and orders antiferromagnetically below 15 K. Here, we present the temperature and field dependent electrical transport of GdTi3Bi4 in different directions. The material exhibits anomalous Hall conductivity (AHC) of 410 S cm-1 at 2 K for B parallel c and it is completely absent for B parallel a, despite the similar magnetization observed in both orientations. This behavior is quite contradictory, as anomalous Hall effect (AHE) typically scales with the magnetization. Through first principles calculations, it is demonstrated that in the presence of time reversal symmetry broken by the Gd 4f sublattice and spin orbit coupling, the magnetization direction controls the orbital mixing in the Ti t2g bands, relocating Berry curvature hot spots and producing the observed orientation selective AHC. The results establish GdTi3Bi4 as platform for investigating new avenues of AHE, such as directional AHE, and thus shed new light on the intricate coupling between magnetic and electronic structures, paving the way for exploring novel quantum phenomena.