High-Throughput Screening MgFe6Ge6-Prototype Bilayer Kagome Family

  • Kagome materials host intertwined phenomena, including nontrivial band topology, superconductivity, and complex charge-density-wave order, making them an important platform in condensed-matter physics and materials science. Motivated by extensive studies on the AV_3Sb_5 family of materials, we perform high-throughput first-principles calculations to screen bilayer kagome AM_6X_6 compounds with an MgFe_6Ge_6-prototype structure as potential weak-coupling superconductors. Thereafter, we systematically evaluate the thermodynamic, dynamic, and magnetic stabilities, followed by electron-phonon coupling (EPC) calculations and superconducting transition temperature estimates based on the Allen-Dynes-modified McMillan equation. From 168 candidates, we identify 31 weak-coupling superconductors that satisfy both the thermodynamic and dynamical stability criteria in our screening workflow. Focusing on compounds without partially filled f shells, we obtain superconducting transition temperatures (T_\rm c) of 0.65-3.97 K with EPC constants \lambda = 0.37-0.62, indicating conventional weak-coupling superconductivity. The EPC is typically driven by vibrations within the kagome layers, with Sn-containing materials exhibiting low-frequency soft modes that contribute significantly to \lambda. By providing a global mapping of stability and weak-coupling superconductivity in bilayer kagome AM_6X_6 compounds, this study offers a practical theoretical database and design principles for future experimental exploration.
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