Topological Crystalline Superconductivity in Dirac Semimetal Phase of Iron-based Superconductors

Abstract

In iron-based superconductors, band inversion of $d$- and $p$-orbitals yields Dirac semimetallic states. We theoretically investigate their topological properties in normal and superconducting phases, based on the tight-binding model involving full symmetry of the materials. We demonstrate that a Cooper pair between electrons with $d$- and $p$-orbitals relevant to the band structure yields odd-parity superconductivity. Moreover, we present the typical surface states by solving the Bogoliubov-de Gennes equation and characterize them by topological invariants defined with crystal symmetry. It is found that there appear various types of Majorana fermions such as surface flat band, Majorana quartet and Möbius twisted surface state. Our theoretical results show that iron-based superconductors are promising platforms to realize rich topological crystalline phases.

9 pages, 6 figures

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• Surface Bogoliubov-Dirac cones and helical Majorana hinge modes in superconducting Dirac semimetals
• Majorana multipole response: General theory and application to wallpaper groups
• Unconventional Majorana fermions on the surface of topological superconductors protected by rotational symmetry
• Dual topological superconducting states in the layered titanium-based oxypnictide superconductor BaTi${}_2$Sb${}_2$O
• Signature of point nodal superconductivity in the Dirac semimetal PdTe
• In the Pursuit of Majorana Modes in Iron-based High-$T_c$ Superconductors
• Representation-protected topology of spin-singlet $s$-wave superconductors
• Photoemission Spectroscopic Evidence of Multiple Dirac Cones in Superconducting BaSn${}_3$
• Possible topological phases in quantum anomalous Hall insulator/unconventional superconductor hybrid systems