论文标题
高压材料中超导性的非谐理论
Anharmonic theory of superconductivity in the high-pressure materials
论文作者
论文摘要
高压下的电子波超导体显示出记录的关键超导温度$ T_C $的最高值，现在快速接近室温。尽管高$ p $超导对于寻求室温超导体的重要性，但缺少对压力及其与声子非谐调性和超导性相互作用的效果的机械理解，因为数值模拟只能将系统特定的详细信息带出控制物理学。在这里，我们在施加的压力下开发了电子 - 音波超导的最小模型，该模型考虑到光子声子的非谐波破坏性。我们发现$ t_c $行为非单调性作为比率$γ/ω_0$的函数，其中$γ$是光学声子阻尼，$ω_0$ $ω_0$零压力和动量处于零压力和动量下。当声子处于变形的边缘时（“ diffuson样”极限）时，对于临界比率$γ/ω_0$进行最佳配对。我们的框架可以深入了解$ t_c $的最新实验观察结果，这是复杂BCS材料Tlinte $ _2 $中压力的函数。
Electron-phonon superconductors at high pressures have displayed the highest values of critical superconducting temperature $T_c$ on record, now rapidly approaching room temperature. Despite the importance of high-$P$ superconductivity in the quest for room-temperature superconductors, a mechanistic understanding of the effect of pressure and its complex interplay with phonon anharmonicity and superconductivity is missing, as numerical simulations can only bring system-specific details clouding out key players controlling the physics. Here we develop a minimal model of electron-phonon superconductivity under an applied pressure which takes into account the anharmonic decoherence of the optical phonons. We find that $T_c$ behaves non-monotonically as a function of the ratio $Γ/ω_0$, where $Γ$ is the optical phonon damping and $ω_0$ the optical phonon energy at zero pressure and momentum. Optimal pairing occurs for a critical ratio $Γ/ω_0$ when the phonons are on the verge of decoherence ("diffuson-like" limit). Our framework gives insights into recent experimental observations of $T_c$ as a function of pressure in the complex BCS material TlInTe$_2$.
