The sensitive tunability of superconducting critical temperature in high-buckled plumbene by shifting Fermi level

Abstract

As the newly member added to the graphene family, the high-buckled (HB) plumbene is a metallic two-dimensional(2D) material with the electronic structure characterized by the existence of some band edges in close proximity to the Fermi level. Hence in such a 2D material the electronic density of states (DOS) presents sharp peaks around the Fermi level. In this work, we perform first-principles calculations of the conventional superconducting critical temperature (Tc) of HB plumbene. We find that the electron-phonon (e-ph) coupling strength which measures the electron mass enhancement is proportional to the DOS at the Fermi level. As a result, Tc of HB plumbene has a sizable increase (from 5.29 K to 17.21 K) when the Fermi level is shifted to the nearby DOS peaks from its intrinsic position. For 2D materials, the adjustment of Fermi level can be readily realized by applying a gate voltage in a device structure of electronic transport, instead of a chemical carrier doping. Therefore, our study proposes a feasible way to tune Tc of those 2D metallic materials such as HB plumbene which have some band edges or flat band around Fermi level.