Abstract
Research into the superconducting characteristics of materials has intrigued scientists for an extended period. This study examines the superconductivity of 3D metallic Haeckelite compounds (XY), characterized by square-octagonal structures and P42/mnm symmetry group. Utilizing first-principles calculations, we have performed a thorough examination of the dynamic stability, electronic structures, and electron-phonon coupling (EPC) in Haeckelite structures containing elements X = B, Be, Ni, Pd, Pt, Cu and Y = C, O, Se, S, Si, Te . Our analysis indicates that 14 compounds demonstrate both mechanical and dynamic stability with superconducting transition temperatures ( Tc ) ranging from ∼ 0.1 K to 15.7 K . Among these, BeC and BC exhibit the highest Tc of 11.3 K and 15.7 K , respectively, with corresponding superconducting gaps of 1.8 meV and 2.4 meV . This study clarifies the relationships between electronic structures, phonon characteristics, and superconductivity in Haeckelite compounds through the application of Eliashberg equations.