New Candidate for Optically Induced Topological Semimetals

Topological Semimetals (TSMs) are a newly discovered phase of matter analogous to Topological Insulators (TIs) but with non-insulating band structures. A number of inversion symmetry breaking compounds have been shown to host TSM phases in equilibrium. TSMs have been predicted to have a range of exotic properties that make them exciting targets for study with both interesting bulk and surface properties.  Here, the compound ZrTe5 is experimentally and theoretically studied toward realizing a non-equilibrium TSM by optical excitation. 

This MRSEC team has demonstrated that single crystals of ZrTe5 exhibit a distinct crossover in their electronic and phononic excitations upon decreasing temperature.  The resulting small Fermi surface structure in this high quality material is found to be an ideal candidate for an optically induced Topological Semimetal with laser light excitation.  This provides a new approach to realizing non-trivial metallic phases out of equilibrium.

L. Fu, J. G. Checkelsky, N. Gedik