Two-dimensional Janus MoSeH with tunable charge density wave, superconductivity and topological properties

Abstract

The coexistence and competition between the well-known quantum phenomena such as superconductivity, charge density wave (CDW), and band topology represent a cutting-edge frontier in the field of condensed matter physics. Two-dimensional (2D) Janus transition metal sulfide hydrides, a family of materials known for hosting diverse quantum phenomena, have drawn extensive attention recently. In this work, based on first-principles calculations, a novel member of this family, named 2H-MoSeH, is predicted. The pristine 2H-MoSeH exhibits CDW induced by electron–phonon coupling. Remarkably, this CDW state can be entirely suppressed under 2% biaxial compressive strain, giving rise to superconducting state with transition temperature ($T_c$) of 24 K. Moreover, CDW can also be suppresed by 0.15 hole doping per primitive cell, leading to superconductivity with a $T_c$ of 17 K while simultaneously inducing a non-trivial band topology. The coexistence and tunable competition among superconductivity, CDW, and band topology in 2H-MoSeH establish it as an ideal platform for exploring novel quantum phenomena and designing new quantum devices.