[Zurück]

E. Martino, I. Crassee, Gaku Eguchi, D. Santos-Cottin, R. Zhong, G. Gu, H. Berger, Z. Rukelj, M. Orlita, C. Homes, A. Akrap:
"Two-Dimensional Conical Dispersion in ZrTe5 Evidence by Optical Spectroscopy";
Physical Review Letters, 122 (2019), 217402.

Zirconium pentatelluride was recently reported to be a 3D Dirac semimetal, with a single conical band, located at the center of the Brillouin zone. The cone´s lack of protection by the lattice symmetry immediately sparked vast discussions about the size and topological or trivial nature of a possible gap opening. Here, we report on a combined optical and transport study of ZrTe5, which reveals an alternative view of electronic bands in this material. We conclude that the dispersion is approximately linear only in the a-c plane, while remaining relatively flat and parabolic in the third direction (along the b axis). Therefore, the electronic states in ZrTe5 cannot be described using the model of 3D Dirac massless electrons, even when staying at energies well above the band gap 2Δ 1⁄4 6 meV found in our experiments at low temperatures.

http://dx.doi.org/10.1103/PhysRevLett.122.217402