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TT: Fachverband Tiefe Temperaturen

TT 23: Topological Insulators and Weyl Semimetals (joint session MA/TT)

TT 23.1: Talk

Tuesday, March 19, 2024, 09:30–09:45, H 2013

behavior of Dirac fermion in non-symmorphic CeTX2 systems — •Sawani Datta^1,4, Khadiza Ali², Rahul Verma¹, Denis Vyalikh³, Bahadur Singh¹, A Thamizhavel¹, Saroj P Dash², and Kalobaran Maiti¹ — ¹Tata Institute of Fundamental Research, Mumbai, India — ²Chalmers University of Technology, Gotheborg, Sweden. — ³DIPC, Donostia, San Sebastian, Spain — ⁴Max Plank Institute for Solid State Research, Stuttgart, Germany

We have studied the behavior of Dirac fermions in the presence of strong electron correlation in nonsymmorphic Kondo lattice systems, CeTX2 (T=Cu/Ag, X-As/Sb) employing high-resolution angle-resolved photoemission spectroscopy [1]. Experiments reveal crossings of highly dispersive linear bands at the Brillouin zone boundary protected by non-symmorphic symmetry [2]. In addition, anisotropic Dirac cones are observed constituted by the square net Sb(As) 5p(4p) states forming a diamond-shaped nodal line. The Dirac bands are linear in a wide energy range with an unusually high slope and exhibit distinct Dirac points in these highly spin-orbit coupled systems. Along with these bulk crossings, CeCuAs2 also exhibits a surface Dirac crossing at the Γ-point. These results seed the emergence of an area of robust topological fermions even in the presence of strong correlation. [1] S. Datta et al. arXiv:2311.05278 [2] L. M. Schoop et al., Nat. Commun. 7, 11696 (2016).

Keywords: nonsymmorphic system; Dirac Fermion; nodal line; strong electron correlation; Kondo lattice system