The effect of antisite defects on the mechanical and dynamic stability of Nb3Al

Lei Han; Zelin Cao; Min Pan; Kaige Hu; Zheng Huang; Jiaming Wang; Yong Zhao; Huiqiu Deng

doi:10.1088/1361-648X/ace9a8

The effect of antisite defects on the mechanical and dynamic stability of Nb₃Al

J Phys Condens Matter. 2023 Aug 1;35(43). doi: 10.1088/1361-648X/ace9a8.

Authors

Lei Han^{1

2}, Zelin Cao¹, Min Pan¹, Kaige Hu³, Zheng Huang⁴, Jiaming Wang⁴, Yong Zhao¹, Huiqiu Deng⁵

Affiliations

¹ Key Laboratory of Magnetic Suspension Technology and Maglev Vehicle, (Ministry of Education), and School of Electric Engineering, Southwest Jiaotong University, Chengdu 610031, People's Republic of China.
² School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, People's Republic of China.
³ Department of Physics, School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, People's Republic of China.
⁴ School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031, People's Republic of China.
⁵ School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China.

PMID: 37478866
DOI: 10.1088/1361-648X/ace9a8

Abstract

The A15-type conventional superconductor Nb₃Al alloys has been considered as an ideal candidate for next generation high field magnets due to its higher superconducting properties and less sensitivity to stain than that of industrialized Nb₃Sn superconductor. First-principles methods are employed to study the potential point defects, vacancy and antisite defects in deviating stoichiometric Nb₃Al alloys and their effect on structure and mechanical properties. Our results show that antisite defects are easier to be produced than vacancy defects, and NbAlantisite defects can keep the tetragonal structure of Nb₃Al. Furthermore, the influence of antisite defects on dynamic stability of Nb₃Al is investigated together with NbAldefects. With the increase of Nb antisite defect content and the formation of orderly arrangement, we found the phonon spectrum yields no more soft phonon modes, which is in contradiction with the dynamical instability of stoichiometric Nb₃Al with no defects. Our calculations indicate Nb antisite defects play a crucial role on the dynamic stability of Nb₃Al compounds.

Keywords: antisite defect; mechanical properties; phonon dispersion; vacancy.