Effects of Nb-vacancies and hydrostatic pressures on the electron density of states of Nb3Sn from first-principles calculations

• Published in: Cryogenics (Guildford) Vol. 108; pp. 103073 - 6
• Main Authors: Luo, Wei, Xie, Xuan, Wang, Keyang, Yang, Lei
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.06.2020; Elsevier BV
• Subjects: Amplitudes; Density functional theory; Density of states; DOS; Electron density; First principles; First-principles calculations; Galling; Hydrostatic pressure; Mathematical analysis; N(EF); Nb-vacancies; Pressure effects; Vacancies; N(EF); First-principles calculations; DOS; Hydrostatic pressure; Nb-vacancies
• ISSN: 0011-2275; 1879-2235
• DOI: 10.1016/j.cryogenics.2020.103073

•Nb-vacancies impose strong influences on both the amplitude and distribution of the electron DOS of Nb3Sn.•The combined effects of Nb-vacancies and hydrostatic pressure can be superposed linearly.•Nb-vacancies suppress the N(EF) of Nb3Sn seriously. The electron density of states is a key parameter to determine the superconducting critical properties of Nb3Sn and its composite wires, which usually work in extreme radiation environments and are subject to strong thermal and electromagnetic loads. In this paper, the contributions of Nb-vacancies and hydrostatic pressure on DOS are investigated by the first-principles calculations based on the density functional theory. The results indicate that Nb-vacancies impose strong influences both on the amplitude and distribution of the electron DOS, namely, the smearing effect and broadening effect, however, hydrostatic pressure only affects slightly the amplitude of DOS with energy in a relatively large range of pressure. The calculations also demonstrate that the combined action of Nb-vacancies and hydrostatic pressure can be superposed linearly. Furthermore, Nb-vacancies suppress the N(EF) of Nb3Sn seriously, and hydrostatic pressure results in an approximately linear decrease of N(EF) with increasing pressure, which coincides well with experimental data.