Multifold degenerated phonon points in the cubic Nb3Bi compound

• Published in: Journal of applied physics 2024-09, Vol.136 (12)
• Main Authors: MSL, Manasa, T., Aiswarya, Ptok, Andrzej, Vaitheeswaran, G.
• Format: Article
• Language: English
• Subjects: A15 compounds; Brillouin zones; Crystal structure; Electronic systems; First principles; Intermetallic compounds; Phonons; Surface properties; Symmetry; Topology
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/5.0219604

Topological materials are receiving significant attention for their distinctive properties and practical applications. Topological states featuring multi-fold band degeneracy are not restricted to electronic systems but also extend to phonon systems. In this investigation, we delved into the higher-order symmetry-constrained topological attributes of Nb 3Bi, an intermetallic compound with a A15 crystal structure. Through the first-principles computations and symmetry evaluation, we tried to describe the topological phonon modes safeguarded by nonsymmorphic symmetries. Our scrutiny revealed that Nb 3Bi possesses notable degeneracy in the phonon dispersion relation, particularly highlighted by a sixfold degenerate point situated at the R point of the Brillouin zone. In addition, we also identified cubic contact Dirac points and quadratic contact triple points at the R and Γ points, respectively. The computed phonon surface states considering two distinct terminations on the (001) and (1 1 ¯0) planes reveal a distinct twofold rotational symmetry arrangement. The present results offer valuable insights into the distinctive phonon attributes and surface characteristics of Nb 3Bi, emphasizing its importance in the field of phonon topology.