Perfect Topological Metal CrB2: A One-Dimensional (1D) Nodal Line, a Zero-Dimensional (0D) Triply Degenerate Point, and a Large Linear Energy Range

Abstract

Topological materials with band-crossing points exhibit interesting electronic characteristics and have special applications in electronic devices. However, to further facilitate the experimental detection of the signatures of these band crossings, topological materials with a large linear energy range around the band-crossing points need to be found, which is challenging. Here, via first-principle approaches, we report that the previously prepared P6/mmm-type CrB2 material is a topological metal with one pair of 1D band-crossing points, that is, nodal lines, in the kz= 0 plane, and one pair of 0D band-crossing points, that is, triple points, along the A–Γ–A’ paths. Remarkably, around these band-crossing points, a large linear energy range (larger than 1 eV) was found and the value was much larger than that found in previously studied materials with a similar linear crossing. The pair of nodal lines showed obvious surface states, which show promise for experimental detection. The effect of the spin–orbit coupling on the band-crossing points was examined and the gaps induced by spin–orbit coupling were found to be up to 69 meV. This material was shown to be phase stable in theory and was synthesized in experiments, and is therefore a potential material for use in investigating nodal lines and triple points.

Hydrostatic pressure-induced anomalous hall effect in Co2FeSi semimetal

“…The search for materials with significant anomalous transport features has gained popularity recently, particularly for TSMs [16]. The TSMs material is one most promising candidates for the 1D NL material and some of these like Fe 3 GeTe 2 ,CrB 2 ,CaP 3 ,LnX (Ln = La, Gd; X = Cl, Br) [17][18][19][20][21] etc exhibits anomalous transport properties which are visible as a transverse voltage drop caused by a longitudinal current that is, only caused by the intrinsic spin-orbit coupling (SOC) and magnetism. The origin of anomalous transport in these materials can arise due to two mechanisms: first, the intrinsic mechanism in which the finite Berry curvature (BC) contributes to anomalous transport properties and the second is the extrinsic mechanism, includes the side jump [22] and skew scattering [23] contribution both of which come from spin-orbit mediated electron scattering off the disorder.…”