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arXiv · 2201.05833

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

L. Chen·L. Q. Zhou·Y. Zhou·C. Liu·Z. N. Guo·S. Y. Gao·W. H. Fan·J. F. Xu·Y. X. Guo·K·Liao·J. O. Wang·H. M. Weng·G. Wang
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Abstract

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.

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L. Chen, L. Q. Zhou, Y. Zhou, C. Liu, Z. N. Guo, S. Y. Gao, W. H. Fan, J. F. Xu, Y. X. Guo, K, Liao, J. O. Wang, H. M. Weng, G. Wang. 2022-01-15. Robust Dirac lines against Ge vacancy and possible spin-orbit Dirac points in nonsymmorphic HfGe0.92Te. https://doi.org/10.1007/s11433-022-1992-x

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