Observation of the anisotropic Dirac cone in the band dispersion of 112-structured iron-based superconductor Ca0.9La0.1FeAs2

Abstract

CaFeAs2 is a parent compound of recently discovered 112-type iron-based superconductors. It is predicted to be a staggered intercalation compound that naturally integrates both quantum spin Hall insulating and superconducting layers and an ideal system for the realization of Majorana modes. We performed a systematical angle-resolved photoemission spectroscopy and first-principle calculation study of the slightly electron-doped CaFeAs2. We found that the zigzag As chain of 112-type iron-based superconductors play a considerable role in the low-energy electronic structure, resulting in the characteristic Dirac-cone like band dispersion as the prediction. Our experimental results further confirm that these Dirac cones only exists around the X but not Y points in the Brillouin zone, breaking the S4 symmetry at iron sites. Our findings present the compelling support to the theoretical prediction that the 112-type iron-based superconductors might host the topological nontrivial edge states. The slightly electron doped CaFeAs2 would provide us a unique opportunity to realize and explore Majorana fermion physics.

5 pages, 4 figures

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Cited by in corpus (6)

• Discovery of a novel 112-type iron-pnictide and La-doping induced superconductivity in Eu1-xLaxFeAs2 (x = 0 ~ 0.15)
• Quasi-2D behavior of 112-type iron-based superconductors
• Site-Selective Antimony Doping in Arsenic Zigzag Chains of 112-type Ca1-xLaxFeAs2
• Weyl states and Fermi arcs in parabolic bands
• Magnetic and superconducting phase diagram of Eu(Fe${}_{1-x}$Ni${}_x$)As${}_2$
• Spin fluctuations in the 112-type iron-based superconductor Ca${}_{0.82}$La${}_{0.18}$Fe${}_{0.96}$Ni${}_{0.04}$As${}_2$