T-六方二氢化钼单层结构稳定性和超导性的理论预测
Theoretical prediction of structural stability and superconductivity in T-hexagonal molybdenum dihydrides Monolayer
浏览论文内容
中文总结 AI 辅助
研究通过第一性原理计算，对比六方二氢化钼单层不同相的能量，确定T相为基态构型。在相关理论框架内评估其晶格动力学和超导性质，发现强电子-声子耦合，预测常压下超导转变温度，凸显该单层是探索低维常规超导的稳定平台。
中文摘要 AI 辅助
在凝聚态物理中，实现富氢材料的常压高温超导仍是主要追求。块状氢化物需极高压力来稳定，二维过渡金属氢化物是有前景的替代方案。本文用第一性原理计算研究六方二氢化钼（MoH2）单层的结构稳定性、电子性质和声子介导的超导性。总能量评估表明八面体T相比之前报道的三角棱柱H相能量上更有利0.198 eV，确定T相为基态构型。接着在密度泛函微扰理论和各向异性Migdal-Eliashberg形式框架内系统评估其晶格动力学和超导性质。过渡金属-氢振动网络诱导强电子-声子耦合，积分耦合参数λ = 1.04。求解各向异性Eliashberg方程预测在常压下常规超导转变温度Tc为14.4K，在5.0K时能隙分布适中（Δ = 2.07 - 3.01meV）。研究突出T-MoH2单层是在环境条件下探索低维常规超导的结构、机械和热稳定平台。
英文摘要
The realization of ambient-pressure, high-temperature superconductivity in hydrogen-rich materials remains a major pursuit in condensed-matter physics. While bulk hydrides require extreme pressures to stabilize, two-dimensional (2D) transition-metal hydrides offer a promising alternative to bypass these compression constraints. In this work, we investigate the structural stability, electronic properties, and phonon-mediated superconductivity of a hexagonal molybdenum dihydride (MoH2) monolayer using first-principles calculations. Total-energy evaluations reveal that the octahedral T-phase is energetically more favorable than the previously reported trigonal prismatic H-phase by 0.198 eV, establishing the T-phase as the true ground-state configuration. Consequently, we systematically evaluate the lattice dynamics and superconducting properties of this ground-state T-MoH2 monolayer within the frameworks of density functional perturbation theory (DFPT) and the anisotropic Migdal-Eliashberg formalism. The transition metal-hydrogen vibrational networks induce strong electron-phonon coupling (EPC), yielding an integrated coupling parameter of λ= 1.04. Solving the anisotropic Eliashberg equations predicts a conventional superconducting transition temperature (Tc of 14.4K) at ambient pressure, characterized by a moderately gap distribution (Δ= 2.07-3.01meV at 5.0 K). Our findings highlight the T-MoH2 monolayer as a structurally, mechanically, and thermally stable platform for exploring low-dimensional conventional superconductivity under ambient conditions.
