First-principles study of electronic properties of B and C doped CuNNi3

Abstract

We have performed ab initio electronic structure calculations for and () alloys using the Green's-function-based Korringa–Kohn–Rostoker method, formulated within atomic sphere approximation. The disorder in sub-lattice is treated within single-site coherent potential approximation. The spin-polarized calculations predict CuNNi3 and its alloys and to be non-magnetic for the entire doping range. For ordered phase, the density of states (DOS) at Fermi energy is mainly composed of Ni 3d states with small contributions from N 2p and Cu 3d states as well. Additionally, we observe a high DOS peak at which arises from Ni and Cu 3d states. For both and alloys, the DOS at Fermi energy decreases monotonically with concentration. This is in sharp contrast to what is expected for a hole doped system with high DOS peak below Fermi energy. The decrease in DOS at Fermi energy is more prominent in alloys. Hence the doping is found to be more deteriorating to superconductivity than . Moreover, the doping induced effects are not entirely rigid-band like, rather a moderate redistribution of electronic states is observed.