Superconducting properties of doped blue phosphorene: Effects of non-adiabatic approach

TL;DR

This study investigates how doping and non-adiabatic effects influence superconductivity in blue phosphorene, revealing high critical temperatures and the importance of Fermi surface topology and phonon-electron interactions.

Contribution

It introduces a detailed first-principles analysis of non-adiabatic effects on superconductivity in doped blue phosphorene, highlighting the role of Fermi surface topology and anisotropic Eliashberg formalism.

Findings

Maximum T_c of 97 K in hole-doped blue phosphorene.

Maximum T_c of 38 K in electron-doped blue phosphorene.

Fermi surface topology critically affects Kohn anomalies and superconductivity.

Abstract

We study the effects of Kohn anomalies on the superconducting properties in electron- and hole-doped cases of monolayer blue phosphorene, considering both adiabatic and non-adiabatic phonon dispersions using first-principles calculations. We show that the topology of the Fermi surface is crucial for the formation of Kohn anomalies of doped blue phosphorene. By using the anisotropic Eliashberg formalism, we further carefully consider the temperature dependence of the non-adiabatic phonon dispersions. In cases of low hole densities, strong electron-phonon coupling leads to a maximum critical temperature of $T_c=97$ K for superconductivity. In electron-doped regimes, on the other hand, a maximum superconducting critical temperature of $T_c=38$ K is reached at a doping level that includes a Lifshitz transition point. Furthermore, our results indicate that the most prominent component of electron-phonon coupling arises from the coupling between an in-plane (out-of-plane) deformation and in-plane (out-of-plane) electronic states of the electron (hole) type doping.