Search

In recent years, the superconducting properties of materials with diamond-like structures have attracted widespread attention. The superconducting transition temperature (Tc) of most diamond-like structures is relatively low, and there has been little research on the superconductivity of ternary diamond-like materials. Here, based on first-principles calculations, we predict B2CX (X = N, P) with P3m1 space group, and reveal that they all exhibit phonon-mediated superconductivity at ambient pressure, with Tc range from 44.3 to 46.1 K, which is higher than most diamond-like superconductors. The coupling between metallic s electrons and softened E phonon (B--C stretching modes) contributes greatly to their superconductivity. Our work provides an important theoretical basis for the experimental design and synthesis of ternary high-temperature superconductors with diamond-like structures. [ABSTRACT FROM AUTHOR]

Although hydrides such as LaH10 are experimentally confirmed to possess high superconducting critical temperature (Tc) of 250-260 K under 170-200 GPa, it is still a tough challenge to be applied. It is highly anticipated to find hydride superconductors with relatively high Tc at low or ambient pressure. Reducing the dimensionality of materials can induce unexpected properties that are distinct from their bulk counterparts, and whether it can modulate the superconducting properties deserves further investigation. Herein, a new 2D monolayer aluminum hydride h-AlH2 is theoretically predicted under ambient pressure based on the first-principles calculations. Since the electronic structures of h-AlH2 reveal the metallicity, the electron-phonon coupling (EPC) and possible phonon-mediated superconductivity are investigated. Based on the isotropic Eliashberg equation, the calculated EPC constant λ of h-AlH2 is 1.16, and the Tc is up to 42.6 K. The EPC mainly originates from the coupling between electrons of Al-s, px, py, and H-s orbitals and the in-plane vibration modes of H atoms. Especially, the Tc can be enhanced to 63.7 K by applying 3% biaxial tensile strain. Thus, the predicted h-AlH2 provides a new platform for finding hydride superconductors in lowdimensional materials at ambient pressure. [ABSTRACT FROM AUTHOR]