论文标题
语音介导的超导性与载体定位之间的竞争
Competition between phonon mediated superconductivity and carriers localization in field-effect doped molybdenum dichalcogenides
论文作者
论文摘要
超导性发生在电化学上掺杂的钼二分法样品中，比四层厚。虽然临界温度（TC）在很大程度上取决于场效应几何形状（单个或双门）和样品（MOS2或MOSE2），但TC总是在高掺杂下饱和。目前尚不清楚配对机理和TC对掺杂，样品和现场效应几何形状的复杂依赖性。以前的理论工作假设单层均匀地掺杂，并将TC饱和度归因于电荷密度波的不稳定性，但是谐波近似中电子波耦合的计算值是基于运输数据的实验估计值的一个数量级。在此，通过执行完全相对论的第一原理计算，该计算考虑了样品厚度，现场效应的几何形状和非谐度，我们排除了在实验性掺杂范围内的电荷密度波的出现，并且证明了与传输数据相吻合的电子量辅助术中一个巨大的降低顺序。通过求解各向异性的Migdal-EliAshberg方程，我们可以解释TC在不同系统和几何形状中的行为。通过对迁移率数据的分析，我们建议TC饱和度是由于载体定位和混乱所致。
Superconductivity occurs in electrochemically doped molybdenum dichalcogenides samples thicker than four layers. While the critical temperature (Tc) strongly depends on the field effect geometry (single or double gate) and on the sample (MoS2 or MoSe2), Tc always saturates at high doping. The pairing mechanism and the complicate dependence of Tc on doping, samples and field-effect geometry are currently not understood. Previous theoretical works assumed homogeneous doping of a single layer and attributed the Tc saturation to a charge density wave instability, however the calculated values of the electron-phonon coupling in the harmonic approximation were one order of magnitude larger than the experimental estimates based on transport data. Here, by performing fully relativistic first principles calculations accounting for the sample thickness, the field-effect geometry and anharmonicity, we rule out the occurrence of charge density waves in the experimental doping range and demonstrate a suppression of one order of magnitude in the electron-phonon coupling, now in excellent agreement with transport data. By solving the anisotropic Migdal-Eliashberg equations, we explain the behaviour of Tc in different systems and geometries. From an analysis of mobility data, we propose that the Tc saturation is due to carriers localization and disorder.
