标题： 高温超导体非平衡状态下的准粒子动力学：配对幅度的迹象而无相位相干 显示英文标题

标题： Quasiparticles dynamics in high-temperature superconductors far from equilibrium: an indication of pairing amplitude without phase coherence

摘要： 我们对最佳掺杂的$\tn{Bi}_2\tn{Sr}_2\tn{CaCu}_2\tn{O}_{8+\delta}$ (Bi-2212) 和$\tn{Bi}_2\tn{Sr}_{2-x}\tn{La}_{x}\tn{Cu}\tn{O}_{6+\delta}$ (Bi-2201) 进行了时间分辨光电子能谱测量。 电子动力学显示，在低于超导相变临界温度时，节点准粒子的非弹性散射减少。 这种电子耗散的下降出人意料地稳健，并且能够承受比长程超导性所能维持的值大得多的光激发密度。 准粒子散射的非常规行为归因于超导关联在与非弹性路径相当的长度尺度上扩展。 我们的测量表明，强驱动的超导体进入一个没有相位相干但具有有限配对幅度的区域。 后者在接近临界温度时消失，并且与角分辨光电子能谱（ARPES）观察到的赝隙没有明显的联系。 显示英文摘要

摘要： We perform time resolved photoelectron spectroscopy measurements of optimally doped $\tn{Bi}_2\tn{Sr}_2\tn{CaCu}_2\tn{O}_{8+\delta}$ (Bi-2212) and $\tn{Bi}_2\tn{Sr}_{2-x}\tn{La}_{x}\tn{Cu}\tn{O}_{6+\delta}$ (Bi-2201). The electrons dynamics show that inelastic scattering by nodal quasiparticles decreases when the temperature is lowered below the critical value of the superconducting phase transition. This drop of electronic dissipation is astonishingly robust and survives to photoexcitation densities much larger than the value sustained by long-range superconductivity. The unconventional behaviour of quasiparticle scattering is ascribed to superconducting correlations extending on a length scale comparable to the inelastic path. Our measurements indicate that strongly driven superconductors enter in a regime without phase coherence but finite pairing amplitude. The latter vanishes near to the critical temperature and has no evident link with the pseudogap observed by Angle Resolved Photoelectron Spectroscopy (ARPES).