Large kagome family candidates with topological superconductivity and charge density waves
Xin-Wei Yi, Xingyu Ma, Zhen Zhang, Zheng-Wei Liao, Jing‐Yang You, Gang Su
Abstract
A group of recently discovered nonmagnetic metal kagome structures ${A\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$ (A = K, Rb, Cs) has aroused widespread interest both experimentally and theoretically due to their unusual charge density wave (CDW) and intertwined superconductivity. However, they all possess weak electron-phonon coupling (EPC) and low superconducting transition temperature ${T}_{c}$. Here, we perform high-throughput first-principles calculations on such kagome candidates with ${A\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$ prototype structure, and propose 24 dynamically stable kagome metals. The calculation based on Bardeen-Cooper-Schrieffer theory shows that most of these metals are superconductors with much stronger EPC than the reported ${A\mathrm{V}}_{3}{\mathrm{Sb}}_{5}$ materials, and their ${T}_{c}$ are between 0.3 and 5.0 K. Moreover, several compounds, such as ${\mathrm{KZr}}_{3}{\mathrm{Pb}}_{5}$ with the highest ${T}_{c}$, are identified as ${\mathbb{Z}}_{2}$ topological metals with clear Dirac cone topological surface states near the Fermi level. In addition, we take ${\mathrm{NaZr}}_{3}{\mathrm{As}}_{5}$ as an example to demonstrate the possible CDW phases. Our results provide rich platforms for exploring various physics with the kagome structure, in which the coexistence of superconductivity and the nontrivial topological nature provides promising insights for the discovery of topological superconductors.