Topological nodal-line fermions in spin-orbit metal PbTaSe2

• DOI: 10.1038/ncomms10556
• Publication Date: 2016-02-02T10:52:27Z
• Authors: Guang Bian; Tay-Rong Chang; Raman Sankar; Su-Yang Xu; Hao Zheng; Titus Neupert; Ching-Kai Chiu; Shin-Ming Huang; Guoqing Chang; Ilya Belopolski; Daniel S. Sanchez; Madhab Neupane; Nasser Alidoust; Chang Liu; BaoKai Wang; Chi-Cheng Lee; Horng-Tay Jeng; Chenglong Zhang; Zhujun Yuan; Shuang Jia; Arun Bansil; Fangcheng Chou; Hsin Lin; M. Zahid Hasan
• Keywords: Topological degeneracy; Point reflection; Surface States

Abstract Topological semimetals can support one-dimensional Fermi lines or zero-dimensional Weyl points in momentum space, where the valence and conduction bands touch. While degeneracy are robust against any perturbation that preserves translational symmetry, nodal require protection by additional crystalline symmetries such as mirror reflection. Here we report, based on a systematic theoretical study detailed experimental characterization, existence of topological nodal-line states non-centrosymmetric compound PbTaSe 2 with strong spin-orbit coupling. Remarkably, not only protected reflection symmetry but also characterized an integer invariant. Our angle-resolved photoemission measurements, first-principles simulations analysis illustrate physical mechanism underlying formation associated surface for first time, thus paving way towards exploring exotic properties fermions condensed matter systems.