The effect of Ni doping on the electronic structure and superconductivity in the noncentrosymmetric ThCoC2

Abstract ThCoC 2 is a non-BCS, noncentrosymmetric superconductor with T c ≃ 2 . 5  K, in which pairing mechanism was suggested to be either spin fluctuations or the electron–phonon coupling. Earlier experimental work revealed that T c can be greatly enhanced upon Ni doping in ThCo 1 − x Ni x C 2 , up to 12 K for x = 0 . 4 . In this work, using the Korringa-Kohn-Rostoker method with the coherent potential approximation (KKR-CPA), the evolution of the electronic structure upon Ni doping was studied and the increase of the density of states at the Fermi level was found. The electron–phonon coupling constant λ was calculated using the rigid muffin tin approximation (RMTA) and the increase in λ ( x ) was found. This indirectly confirms the electron–phonon coupling scenario as the trend in λ ( x ) is in qualitative agreement with the experiment when the electron–phonon pairing is assumed.