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

ThCoC2 is a non-BCS, noncentrosymmetric superconductor with T-c similar or equal to 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 ThCo1-xNixC2, 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 lambda was calculated using the rigid muffin tin approximation (RMTA) and the increase in lambda(x) was found. This indirectly confirms the electron-phonon coupling scenario as the trend in lambda(x) is in qualitative agreement with the experiment when the electron-phonon pairing is assumed.

Automated summary

In this study, the effect of Ni doping on the electronic structure of ThCoC2 superconductor was investigated using the KKR-CPA method, revealing an increase in the density of states at the Fermi level. The electron-phonon coupling constant lambda was also calculated using the RMTA method, showing an increase in lambda(x). These findings support the assumption of electron-phonon coupling as the pairing mechanism.