Hydrogenation-induced superconductivity in monolayer

¹ Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics, South China Normal University - Guangzhou 510006, China
² Guangdong Provincial Key Laboratory of Nuclear Science, Institute of Quantum Matter, South China Normal University - Guangzhou 510006, China
³ School of Cyber Security, Guangdong Polytechnic Normal University - Guangzhou 510665, China

Received: 15 January 2024
Accepted: 20 February 2024

Abstract

Here, we construct a new two-dimensional hydrogenated transition metal dichalcogenide material, the Janus WSH monolayer, which is created by replacing the top-layer S atoms in the 2H-WS₂ monolayer with H atoms. Then we use first-principles calculations to investigate its electronic structure, phonon dispersion, and superconductivity. The results show that hydrogenation breaks the reflection symmetry, which helps orbital hybridization and to flatten the electronic bands. Thus, it leads to a high electronic density of states near the Fermi level. Additionally, the electron-phonon coupling is enhanced by the softening of phonon modes from the in-plane vibrations of W. The strong interactions between electrons and phonons result in phonon-mediated superconductivity in Janus WSH monolayer. The calculated critical temperature (T_c) is approximately 23.1 K at atmospheric pressure. This T_c is about twice higher than that of existing WS₂-based materials.