Quasi-Dirac points in electron-energy spectra of crystals

Abstract

Specific properties, such as surface Fermi arcs, features of quantum oscillations and of various responses to a magnetic field, distinguish Dirac semimetals from ordinary materials. These properties are determined by Dirac points at which a contact of two electron-energy bands occurs and in the vicinity of which these bands disperse linearly in the quasimomentum. This work shows that almost the same properties are inherent in a wider class of materials in which the Dirac spectrum can have a noticeable gap comparable with the Fermi energy. In other words, the degeneracy of the bands at the point and their linear dispersion are not necessary for the existence of these properties. The only sufficient condition is the following: In the vicinity of such a quasi-Dirac point, the two close bands are well described by a two-band model that takes into account the strong spin-orbit interaction. To illustrate the results, the spectrum of ZrTe${}_5$ is considered. This spectrum contains a special quasi-Dirac point, similar to that in bismuth.

4 figures, 10 pages+4 pages of Supplementary Information. This version of the article has been accepted for publication in Communications Physics

References in corpus (8)

• Linear magnetoresistance caused by mobility fluctuations in the n-doped Cd3As2
• Universal phase diagrams for the quantum spin Hall systems
• Magnetic susceptibility of topological nodal semimetals
• Thermodynamic signatures for the existence of Dirac electrons in ZrTe5
• Temperature dependence of the energy band gap in ZrTe${}_5$: implications for the topological phase
• Band Structure Driven Thermoelectric Response of Topological Semiconductor ZrTe${}_5$
• Revealing temperature evolution of the Dirac band in ZrTe${}_5$ via magneto-infrared spectroscopy
• Phase of quantum oscillation in Weyl semimetals

Cited by in corpus (1)

• Model for charge carrier spectra in topological semimetals of the TaAs family