Recently, the transition metal dichalcogenide (TMD) system 2M-WS₂ has been identified as a Dirac semimetal exhibiting both superconductivity with the highest T_c ~ 8.5 K among all the TMD materials and topological surface states. Here we report on muon spin rotation (μSR) and density functional theory studies of microscopic SC properties and the electronic structure in 2M-WS₂ at ambient and under hydrostatic pressures (p_max = 1.9 GPa). The SC order parameter in 2M-WS₂ is determined to have single-gap s-wave symmetry. We further show a strong negative pressure effect on T_c and on the SC gap Δ. This may be partly caused by the pressure induced reduction of the size of the electron pocket around the Γ-point. We also find that the superfluid density n_s is weakly affected by pressure. The absence of a strong pressure effect on n_s and the absence of a correlation between n_s and T_c in 2M-WS₂, in contrast to the other SC TMDs T_d-MoTe₂ and 2H-NbSe₂, is explained in terms of its location in the optimal (ambient pressure) and above the optimal (under pressure) superconducting regions of the phase diagram and its large distance to the other possible competing or cooperating orders.

最近，过渡金属二硫属化物（TMD）系统2M-WS ₂已经被鉴定为狄拉克半金属兼具超导具有最高Ť _Ç  〜8.5所有的TMD的材料和表面拓扑状态之间ķ。在这里，我们报告有关在室温和静水压力（p _max  = 1.9 GPa）下2M-WS ₂中的微观SC特性和电子结构的μ自旋旋转（μSR）和密度泛函理论研究。确定2M-WS _2中的SC阶参数具有单间隙s波对称性。我们进一步显示出对T _c的强烈负压效应并且在SC间隙Δ上。这可能部分是由于压力引起的电子点在Γ点附近尺寸的减小而引起的。我们还发现，超流密度ñ_小号弱受压力。没有强大的压力作用Ñ_小号和不存在之间的相关性的Ñ_小号和Ť _Ç在2M-WS ₂，相比于其他SC TMD的Ť _d -MoTe ₂和2H-NbSe ₂根据其在相图的最佳（环境压力）中和在最佳（负压）超导区域之上的位置以及与其他可能的竞争或合作顺序的较大距离来进行解释。