Abstract
Recent interest in topological nature in condensed matter physics has revealed the essential role of Berry curvature in anomalous Hall effect (AHE). However, since large Hall response originating from Berry curvature has been reported in quite limited materials, the detailed mechanism remains unclear at present. Here, we report the discovery of a large AHE triggered by a pressure-induced magnetic phase transition in elemental $\alpha$-Mn. The AHE is absent in the non-collinear antiferromagnetic phase at ambient pressure, whereas a large AHE is observed in the weak ferromagnetic phase under high pressure despite the small averaged moment of $\sim 0.02 \mu_B$/Mn. Our results indicate that the emergence of the AHE in $\alpha$-Mn is governed by the symmetry of the underlying magnetic structure, providing a direct evidence of a switch between a zero and non-zero contribution of the Berry curvature across the phase boundary. $\alpha$-Mn can be an elemental and tunable platform to reveal the role of Berry curvature in AHE.
Highlights
The anomalous Hall effect (AHE) in systems with broken time-reversal symmetry is one of the fundamental transport phenomena in condensed matter physics [1]
Our results indicate that the occurrence of the AHE is determined by the symmetry of the underlying magnetic structure, which is a remarkable evidence of the switch between the zero and nonzero contributions of the Berry curvature across the phase boundary
We confirmed that the pressure dependences of the antiferromagnetic phase (TN) and TA agree with the previous result [31]
Summary
The anomalous Hall effect (AHE) in systems with broken time-reversal symmetry is one of the fundamental transport phenomena in condensed matter physics [1]. The Hall resistivity ρyx is represented as ρyx = ρyNx + ρyAx [2,3]. ΡyNx is the normal component due to the Lorentz force, whereas ρyAx represents the anomalous component observed in an magnetically ordered phase, which becomes empirically larger when the system has a larger spontaneous magnetization (M). Recent interest in topological nature in condensed matter physics has provided insight into the “intrinsic” origin of the AHE [7], which is reinterpreted to be Hall response due to the Berry curvature in the momentum space [8,9,10,11,12]. The anomalous Hall conductivity σxAy is represented by the Kubo formula as [10,11]
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