Large kagome family candidates with topological superconductivity and charge density waves

ABSTRACT

A group of recently discovered nonmagnetic metal kagome structures 𝐴⁢V3⁢Sb5 (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 𝑇𝑐. Here, we perform high-throughput first-principles calculations on such kagome candidates with 𝐴⁢V3⁢Sb5 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⁢V3⁢Sb5 materials, and their 𝑇𝑐 are between 0.3 and 5.0 K. Moreover, several compounds, such as KZr3⁢Pb5 with the highest 𝑇𝑐, are identified as ℤ2 topological metals with clear Dirac cone topological surface states near the Fermi level. In addition, we take NaZr3⁢As5 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.