First-principles exploration of superconductivity in intercalated bilayer borophene phases

TL;DR

This study uses first-principles calculations to investigate phonon-mediated superconductivity in intercalated bilayer borophene, revealing high critical temperatures up to 58 K and highlighting their potential as resilient 2D superconductors.

Contribution

It demonstrates that intercalation with specific elements enhances superconductivity in bilayer borophene, with higher $T_{c}$ than monolayer forms, using systematic first-principles and Eliashberg calculations.

Findings

Intercalation with alkaline-earth elements yields highest $T_{c}$.

Superconducting $T_{c}$ up to 58 K achieved.

Intercalated bilayer borophene more resilient and superconducting than monolayer.

Abstract

We explore the emergence of phonon-mediated superconductivity in bilayer borophenes by controlled intercalation with elements from the groups of alkali, alkaline-earth, and transition metals, using systematic first-principles and Eliashberg calculations. We show that the superconducting properties are primarily governed by the interplay between the out-of-plane ($p_{z}$) boron states and the partially occupied in-plane ($s+p_{x,y}$) bonding states at the Fermi level. Our Eliashberg calculations indicate that intercalation with alkaline-earth elements leads to the highest superconducting critical temperatures ($T_{c}$). Specifically, Be in $\delta_{4}$, Mg in $\chi_{3}$, and Ca in the kagome bilayer borophene demonstrate superior performance with $T_{c}$ reaching up to 58~K. Our study therefore reveals that intercalated bilayer borophene phases are not only more resilient to chemical deterioration, but also harbor enhanced $T_{c}$ values compared to their monolayer counterparts, underscoring their substantial potential for the development of boron-based two-dimensional superconductors.