Unpaired Weyl phonon systems in NaHPO3NH2

Authors

Ying Yang, Chongqing Normal University
Feng Zhou, Southwest University
Jianhua Wang, Southwest University
Ying Liu, Hebei University of Technology
Yuting Cui, Chongqing Normal University
Guangqian Ding, Chongqing University of Posts and Telecommunications
Xiaotian Wang, Southwest University

Publication Name

Applied Physics Letters

Abstract

Phonon-based Weyl points (WPs) are usually considered to appear in pairs with opposite chirality. Here, we report the phonon dispersion in a realistic material monosodium phosphoramidate, NaHPO3NH2, which has two types of unpaired WP phonon systems: (i) two hourglass charge-3 (C-3) WPs and six C-1 conventional WPs forming a topological Weyl complex; (ii) one C-2 WP, with a topologically charged Weyl nodal surface, forming a topologically charged Weyl point-surface system. Remarkably, the simultaneous presence of the C-1, C-2, and hourglass C-3 WPs in NaHPO3NH2 results in the formation of clean and long phononic double and sextuple-helicoid surface states on the (10 1 ¯ 0) and (001) surfaces, respectively. The phononic double and sextuple-helicoid surface states span the entire first surface Brillouin zones of the (10 1 ¯ 0) and (001) surfaces, which will facilitate their detection in future experimental studies.

Open Access Status

This publication may be available as open access

Volume

122

Issue

23

Article Number

232202

Funding Number

12004096

Funding Sponsor

National Natural Science Foundation of China