Superconductivity in two-dimensional MB4 (M = V, Nb, and Ta)

Abstract

The study of two-dimensional (2D) superconductors is one of the most prominent areas in recent years and has remained a long-standing scientific challenge. Since the introduction of the new member of 2D material family consisting of transition-metal elements with Borides (MBenes), the study of various properties of 2D metal borides has attracted widespread interest. In this work, we systematically investigate the phonon-mediated superconductivity in 2D MB4 (M = V, Nb, and Ta), by using the first-principles calculations. Starting from the dynamical stabilities of these structures, we perform a detailed analysis of the electron-phonon coupling and superconductivity of AB-stacked MBenes by solving the anisotropic Eliashberg equation. NbB4 has the largest electron-phonon coupling and the highest superconducting transition temperature T c of 35.4 K. Our study broadens the 2D superconducting boride family, which is of great significance for the study of 2D superconductivity.