Using Ultrafast Photocurrents to Manipulate Electronic Symmetry in the Weyl Semimetal TaAs

Topological semimetals are sensitive to a breaking and restoring of symmetry, which affect both bulk and surface electronic states. Using terahertz emission and second harmonic generation spectroscopy as sensitive probes for symmetry change, we observe an all-electronic mechanism of photoinduced symmetry breaking rooted in photocurrent generation.