The multiple properties in two-dimensional (2D) materials have attracted widespread attention. Utilizing first-principles calculations, we theoretically predict four 2D transition metal Janus sulfide hydrides, named 2H/1T-WH ( = S, Se). The 2H-WSH and 2H–WSeH demonstrate superconductivity with critical temperatures () of 13.4 K and 11.4 K, respectively. Whereas 1T-WSH and 1T-WSeH display charge density wave (CDW) properties arising from electron-phonon coupling (EPC). It is noteworthy that the CDW can be suppressed through biaxial compressive strain, leading to the emergence of superconductivity with of 12.2 K and 11.9 K for 1T-WSH (−2 %) and 1T-WSeH (−4 %), respectively. The superconductivity of the above materials originates from the coupling between W-3 electrons and the low-frequency vibrations of W. Interestingly, the 2H–WSeH and 1T-WSeH (−4 %) display nontrivial topological properties, as evidenced by topological invariant and the presence of edge states. Our research not only provides theoretical guidance for further exploring 2D Janus materials, but also provides ideas for the competition of multiple orders in 2D materials.

中文翻译：

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二维 Janus 2H/1T-WXH (X = S, Se) 中电荷密度波、超导性和拓扑特性的预测


二维（2D）材料的多种特性引起了广泛的关注。利用第一性原理计算，我们理论上预测了四种二维过渡金属 Janus 硫化物氢化物，命名为 2H/1T-WH ( = S, Se)。 2H-WSH 和 2H-WSeH 表现出超导性，临界温度 () 分别为 13.4 K 和 11.4 K。而 1T-WSH 和 1T-WSeH 显示由电子声子耦合 (EPC) 产生的电荷密度波 (CDW) 特性。值得注意的是，CDW 可以通过双轴压缩应变来抑制，导致 1T-WSH (-2 %) 和 1T-WSeH (-4 %) 分别出现 12.2 K 和 11.9 K 的超导性。上述材料的超导性源于 W-3 电子与 W 的低频振动之间的耦合。有趣的是，2H–WSeH 和 1T-WSeH (−4 %) 显示出非平凡的拓扑性质，拓扑不变性和边缘态的存在。我们的研究不仅为进一步探索二维Janus材料提供了理论指导，也为二维材料的多阶竞争提供了思路。