Possible experimental realization of a basic Z 2 topological semimetal in GaGeTe


We report experimental and theoretical evidence that GaGeTe is a basic Z2 topological semimetal with three types of charge carriers: bulk-originated electrons and holes as well as surface state electrons. This electronic situation is qualitatively similar to the classic 3D topological insulator Bi2Se3, but important differences account for an unprecedented transport scenario in GaGeTe. High-resolution angle-resolved photoemission spectroscopy combined with advanced band structure calculations show a small indirect energy gap caused by a peculiar band inversion at the T-point of the Brillouin zone in GaGeTe. An energy overlap of the valence and conduction bands brings both electron and holelike carriers to the Fermi level, while the momentum gap between the corresponding dispersions remains finite. We argue that peculiarities of the electronic spectrum of GaGeTe have a fundamental importance for the physics of topological matter and may boost the material's application potential.

Gallium compounds, Photoelectron spectroscopy, Tellurium compounds, Topological insulators, Topology, Band structure calculation, Brillouin zones, Electronic spectrum, Electrons and holes, Experimental realizations, High-resolution angle-resolved photoemission spectroscopies, Holelike carriers, Surface-state electrons, Germanium compounds
Haubold, E., Fedorov, A., Pielnhofer, F., Rusinov, I. P., Menshchikova, T. V., Duppel, V., et al. (2019). Possible experimental realization of a basic Z 2 topological semimetal in GaGeTe. 7(12). https://doi.org//10.1063/1.5124563
CC BY 4.0 Unported