The Superconducting Phase Diagram of ThFe_1-xNi_xAsN

Differently from most of the other 1111-type iron-based superconductors (IBSCs), ThFeAsN without an antiferromagnetic order shows superconductivity at 30 K in the absence of chemical doping and other treating. In order to enhance its superconductivity and understand its peculiar superconducting behaviour, it is necessary to investigate the evolution of the superconducting phase through electron doping, especially heavy electron doping. Chemically, the doping of Ni is an effective way to realize heavy electron doping, as Ni atoms have two more 3d electrons than Fe atoms and electrons could be doped directly into the FeAs planes. As is known that ThFeAsN is a kind of unconventional superconductor, while ThNiAsN is a kind of conventional superconductor, then if ThFeAsN is doped with Ni to form ThFe1-xNixAsN, some intriguing behaviours such as the phase transition from unconventional superconductivity to conventional superconductivity may be observed. Here, we have synthesized ThFe1-xNixAsN with 0.01