Martino E, Crassee I, Eguchi G, Santos-Cottin D, Zhong R D, Gu G D, Berger H, Rukelj Z, Orlita M, Homes C C, Akrap Ana
IPHYS, EPFL, CH-1015 Lausanne, Switzerland.
LNCMI, CNRS-UGA-UPS-INSA, 25, Avenue des Martyrs, F-38042 Grenoble, France.
Phys Rev Lett. 2019 May 31;122(21):217402. doi: 10.1103/PhysRevLett.122.217402.
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 ZrTe_{5}, 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 ZrTe_{5} cannot be described using the model of 3D Dirac massless electrons, even when staying at energies well above the band gap 2Δ=6 meV found in our experiments at low temperatures.
最近有报道称五碲化锆是一种三维狄拉克半金属，具有一个位于布里渊区中心的单锥形能带。由于该锥形不受晶格对称性的保护，这立即引发了关于可能打开的能隙大小以及拓扑或平凡性质的广泛讨论。在此，我们报告了对ZrTe₅的光学和输运联合研究，该研究揭示了这种材料中电子能带的另一种观点。我们得出结论，色散仅在a - c平面内近似线性，而在第三个方向（沿b轴）保持相对平坦且呈抛物线状。因此，即使处于远高于我们在低温实验中发现的带隙2Δ = 6 meV的能量下，ZrTe₅中的电子态也不能用三维无质量狄拉克电子模型来描述。
