Ultrafast electron relaxation in superconducting Bi2Sr2CaCu2O8+δ by time-resolved photoelectron spectroscopy
Ultrafast electron relaxation in superconducting Bi2Sr2CaCu2O8+δ by time-resolved photoelectron spectroscopy
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DOI：
10.1103/physrevlett.99.197001
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发表时间：
2007-11-09
影响因子：
8.6
通讯作者：
Wolf, M.
中科院分区：
文献类型：
--
作者：
Perfetti, L.;Loukakos, P. A.;Wolf, M.
利用时间分辨光电子能谱研究了最佳掺杂Bi_2Sr_2CaCu_2O_（8 + δ）（Bi-2212）中光激发电子的动力学行为。热电子在小于50 fs的时间内热化，并在两个不同的时间尺度（110 fs和2 ps）上耗散能量。这些都归因于非平衡声子的产生和随后的衰减，分别。我们得出的结论是，20%的总晶格模式占主导地位的耦合强度和估计的Eliashberg耦合函数λ Ω（2）（0）=360 +/- 30 meV（2）的第二动量。对于铜-氧键的典型声子能量（Ω（0）类似于或等于40-70 meV），这导致平均电子-声子耦合λ < 0.25。
Time-resolved photoelectron spectroscopy is employed to study the dynamics of photoexcited electrons in optimally doped Bi2Sr2CaCu2O8+delta (Bi-2212). Hot electrons thermalize in less than 50 fs and dissipate their energy on two distinct time scales (110 fs and 2 ps). These are attributed to the generation and subsequent decay of nonequilibrium phonons, respectively. We conclude that 20% of the total lattice modes dominate the coupling strength and estimate the second momentum of the Eliashberg coupling function lambda Omega(2)(0)=360 +/- 30 meV(2). For the typical phonon energy of copper-oxygen bonds (Omega(0)similar or equal to 40-70 meV), this results in an average electron-phonon coupling lambda < 0.25.