Issue 41, 2022

Movable triple points and Dirac points in centrosymmetric AB2 (A = Cr, Mo; B = Si, Ge) compounds

Abstract

Topological semimetals with nontrivial band crossing points have attracted widespread interest in recent years. Here, we propose that AB2 (A = Cr, Mo; B = Si, Ge) compounds are topological semimetals that feature a pair of triple points (TPs) on high-symmetry paths in the absence of spin–orbital coupling (SOC). In particular, the existence of this kind of TP is accompanied by a quadratic nodal line (QNL). In addition, we discover that these TPs are movable. Under a triaxial strain, we can change their positions on high-symmetry paths. When considering SOC, TPs transform into two pairs of type-II Dirac points along the high-symmetry path. Akin to TPs without SOC, each pair of Dirac points can also shift their positions on the high-symmetry paths under a triaxial strain. To characterize this property of TPs and Dirac points, we construct an effective model around the TPs and Dirac points, finding that there indeed exists a parameter that could characterize the movable properties for the TPs and Dirac points. According to the bulk-surface correspondence, we also discover that the length of the Fermi arcs that correspond to the nontrivial band crossings are also altered when changing their positions. Meanwhile, the shapes of Fermi arcs are also changed. Therefore, our work provides a platform to study the band crossings that are movable. The controllable fermions are beneficial to utilize the topological materials in nano-devices.

Graphical abstract: Movable triple points and Dirac points in centrosymmetric AB2 (A = Cr, Mo; B = Si, Ge) compounds

Supplementary files

Article information

Article type
Paper
Submitted
19 Jul 2022
Accepted
27 Sep 2022
First published
28 Sep 2022

Phys. Chem. Chem. Phys., 2022,24, 25403-25410

Movable triple points and Dirac points in centrosymmetric AB2 (A = Cr, Mo; B = Si, Ge) compounds

Y. Zhang, X. Dai, T. He, W. Liu, L. Wang, W. Yu, L. Xu, Y. Liu, X. Zhang and G. Liu, Phys. Chem. Chem. Phys., 2022, 24, 25403 DOI: 10.1039/D2CP03297J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements