ABSTRACT
High-purity 1T'-WS2 film has been experimentally synthesized [Nature Materials, 20, 1113-1120 (2021)] and theoretically predicted to be a two-dimensional (2D) superconducting material with Dirac cones [arXiv:2301.11425]. In the present work, we further study the superconducting properties of monolayer 1T'-WS2 by applying biaxial tensile strain. It is shown that the superconducting critical temperature Tc firstly increases and then decreases with respect to tensile strains, with the highest superconducting critical temperature Tc of 7.25 K under the biaxial tensile strain of 3%. In particular, we find that Dirac cones also exist in several tensile strained cases. Our studies show that monolayer 1T'-WS2 may provide a good platform for understanding the superconductivity of 2D Dirac materials.
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.
