Phonon-Mediated Superconductivity near the Lattice Instability in Hole-doped Hydrogenated Monolayer Hexagonal Boron Nitride

TL;DR

This study predicts that hole-doped hydrogenated monolayer hexagonal boron nitride can exhibit phonon-mediated superconductivity with a transition temperature potentially reaching 82 K under strain, near lattice instability.

Contribution

It demonstrates the possibility of high-temperature phonon-mediated superconductivity in hydrogenated h-BN near lattice instability through first-principles calculations.

Findings

Superconductivity with Tc up to 31 K at certain doping levels.

Enhanced Tc up to 82 K under biaxial tensile strain.

Stability of hole-doped H2BN at low doping levels.

Abstract

Employing the density-functional theory with local density approximation, we show that the fully hydrogenated monolayer-hexagonal boron nitride (H$_2$BN) has a direct-band gap of 2.96 eV in the blue-light region while the pristine $\textit{h}$-BN has a wider indirect-band gap of 4.78 eV. The hole-doped H$_2$BN is stable at low carrier density ($n$) but becomes dynamically unstable at higher $n$. We predict that it is a phonon-mediated superconductor with a transition temperature ($T_c$) which can reach $\sim$31 K at $n$ of $1.5\times$ $10^{14}$ holes cm$^{-2}$ near the lattice instability. The $T_c$ could be enhanced up to $\sim$82 K by applying a biaxial tensile strain at 6 % along with doping at $n$ of $3.4\times$ 10$^{14}$ holes cm$^{-2}$ close to a new lattice instability.