Pairing symmetry in the iron-pnictide superconductor KFe₂As₂

¹ Department of Physics and State Key Laboratory of Surface Physics, Fudan University - Shanghai 200433, China
² Texas Center for Superconductivity and Department of Physics, University of Houston - Houston, TX 77204, USA
³ Theoretical Division, Los Alamos National Laboratory - Los Alamos, NM 87545, USA

Received: 27 June 2012
Accepted: 8 August 2012

Abstract

The pairing symmetry is one of the major issues in the study of iron-based superconductors. We adopt a ten-orbital model by using the maximally localized Wannier functions based on the first-principles band structure calculations combined with the J₁-J₂ model for KFe₂As₂, the phase diagram of pairing symmetries is constructed. We find that the pairing symmetry for KFe₂As₂ is a nodal (s_x²y² + s_x²+y²)-wave in the folded Brillouin zone with two iron atoms per unit cell. This pairing symmetry can explain the experiments observed nodes, and it also can be tested by future experiments.