1. High-pressure control of optical nonlinearity in the polar Weyl semimetal TaAs
- Author
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Li, Chen, Li, Xiang, Deshpande, T., Li, Xinwei, Nair, N., Analytis, J. G., Silevitch, D. M., Rosenbaum, T. F., and Hsieh, D.
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Mesoscale and Nanoscale Physics ,Physics - Optics - Abstract
The transition metal monopnictide family of Weyl semimetals recently has been shown to exhibit anomalously strong second-order optical nonlinearity, which is theoretically attributed to a highly asymmetric polarization distribution induced by their polar structure. We experimentally test this hypothesis by measuring optical second harmonic generation (SHG) from TaAs across a pressure-tuned polar-to-nonpolar structural phase transition. Despite the high-pressure structure remaining noncentrosymmetric, the SHG yield is reduced by more than 60 % by 20 GPa as compared to the ambient pressure value. By examining the pressure dependence of distinct groups of SHG susceptibility tensor elements, we find that the yield is primarily controlled by a single element that governs the response along the polar axis. Our results confirm a connection between the polar axis and the giant optical nonlinearity of Weyl semimetals and demonstrate pressure as a means to tune this effect $in$ $situ$., Comment: 5 pages main text, 4 figures, 2 pages supplementary information
- Published
- 2022
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