Hydrogenation induced high-temperature superconductivity in two-dimensional W2C3.

Abstract

The discovery of highly crystalline two-dimensional (2D) superconductors provides a new alluring branch for exploring the fundamental significances. Based on first-principles calculations, we predict a new kind of 2D stable material W2C3, which is a semimetal but not a superconductor because of the weak electron-phonon coupling (EPC) strength. After hydrogenation, W2C3H2 possesses the intrinsic metallic properties with a large density of states (DOS) at the Fermi energy (EF). More interestingly, the EPC strength is greatly enhanced after hydrogenation and the calculated critical temperature (Tc) is 40.5 K. Furthermore, the compressive strain can obviously soften the low-frequency phonons and enhance the EPC strength. Then, the Tc of W2C3H2 can be increased from 40.5 K to 49.1 K with -4% compressive strain. This work paves the way for providing a new platform for 2D superconductivity.