Robust Dirac lines against Ge vacancy and possible spin-orbit Dirac points in nonsymmorphic HfGe0.92Te

• Published in: arXiv.org
• Main Authors: Chen, L, Zhou, L Q, Zhou, Y, Liu, C, Guo, Z N, Gao, S Y, Fan, W H, Xu, J F, Guo, Y X, K, Liao, Wang, J O, Weng, H M, Wang, G
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 15.01.2022
• Subjects: Crystal growth; Crystal structure; Magnetoresistance; Magnetoresistivity; Photoelectric emission; Physics - Materials Science; Physics - Strongly Correlated Electrons; Robustness; Single crystals; Spin-orbit interactions; Topology; Vacancies
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2201.05833

Looking for new materials with Dirac points has been a fascinating subject of research. Here we report the growth, crystal structure, and band structure of HfGe0.92Te single crystals, featuring three different types of Dirac points. HfGe0.92Te crystalizes in a nonsymmorphic tetragonal space group P4/nmm (No. 129), having square Ge-atom plane with vacancies about 8%. Despite the vacancies on Ge site, the Dirac nodal line composed of conventional Dirac points vulnerable to spin-orbit coupling (SOC) is observed using angle-resolved photoemission spectroscopy, accompanied with the robust Dirac line protected by the nonsymmorphic symmetry against both SOC and vacancies. Specially, spin-orbit Dirac points (SDPs) originated from the surface formed under SOC are hinted to exist according to our experiments and calculations. Quasi-two-dimensional (quasi-2D) characters are observed and further confirmed by angular-resolved magnetoresistance. HfGe0.92Te is a good candidate to explore exotic topological phases or topological properties with three different types of Dirac points and a promising candidate to realize 2D SDPs.