Nonlinear Hall effect in the spin-valley locked Dirac semimetal BaMnSb<sub>2</sub>
ORAL
Abstract
In time-reversal invariant materials, Berry curvature dipole (BCD) gives rise to an anomalous nonlinear Hall effect (NLHE) when the inversion symmetry is broken. Although NLHE is observed in bilayer[1] and few-layer[2] WTe2, BCD-induced NLHE in bulk single-crystals remains elusive. In this talk, we will report a bulk NLHE in a spin-valley locked Dirac semimetal BaMnSb2[3]. In this material, the distorted Sb zig-zag chains generate two gapped Dirac cones with spin-valley locking near the X point in the Brillouin zone, which creates a BCD. Our experiments show when an alternating current flows along the zig-zag chain direction across the crystal, a second-order Hall signal is present and exhibits the quadratic dependence on current. Through structure and domain tuning, we further demonstrate the observed NLHE is intrinsic. This finding shows NLHE measurements can serve as a probe for Berry curvature for non-centrosymmetric bulk crystals.
[1] Q. Ma, et al., Nature 565, 337 (2019).
[2] K. Kang, et al., Nat. Mater. 18, 324 (2019).
[3] J. Y. Liu, et al., ArXiv:1907.06318.
[1] Q. Ma, et al., Nature 565, 337 (2019).
[2] K. Kang, et al., Nat. Mater. 18, 324 (2019).
[3] J. Y. Liu, et al., ArXiv:1907.06318.
*This work was supported by the Penn State Center for Nanoscale Science, an NSF MRSEC under grant DMR-1420620.
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Presenters
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Lujin Min
- Department of Material Science and Engineering, Penn State University
- Department of Physics, Pennsylvania State University
- Physics, Pennsylvania State University
- Pennsylvania State University
- Department of Materials Science and Engineering, Pennsylvania State University