Measuring non-abelian Berry curvature in strained gallium arsenide using electron-hole collisions*

Berry curvature is a key quantity in characterizing the band topology of materials [1]. However, measuring Berry curvature locally in the Brillouin zone (BZ) remains challenging due to decoherence from rapid scattering processes. High-order sideband generation (HSG) avoids this difficulty by using a strong terahertz field to drive electron-hole pairs to collision before scattering. Polarimetry of sidebands has been shown to be sensitive to the local Berry curvature and the Bloch wavefunctions of semiconductors [2,3]. In strained gallium arsenide (GaAs), there is a non-abelian Berry curvature in the valence bands near the BZ center. Here we present a measurement of this non-abelian Berry curvature in GaAs using HSG. We also discuss future applications of this method to characterizing topological materials.

References
[1]
C. Nayak, et al. , "Non-Abelian anyons and topological quantum computing," Rev. Mod. Phys. 80, 1083-, 2008.

[2]
H. B. Banks, Q. Wu, D. C. Valovcin, et al. , "Dynamical Birefringence: Electron-Hole Recollisions as Probes of Berry Curvature," Phys. Rev. X 7, 041042, 2019.

[3]
J. B. Costello, S. D. O'Hara, Q. Wu, et al., Manuscript in Preparation.