Role of Spin-Flip Exchange Scattering for Hot-Electron Lifetimes in Cobalt
Role of Spin-Flip Exchange Scattering for Hot-Electron Lifetimes in Cobalt
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DOI：
10.1103/physrevlett.107.026601
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发表时间：
2011-07-05
影响因子：
8.6
通讯作者：
Weinelt, M.
中科院分区：
文献类型：
--
作者：
Goris, A.;Doebrich, K. M.;Weinelt, M.
利用自旋和时间分辨双光子光电发射研究了fcc Co薄膜中热电子的自旋依赖寿命。即使激发能接近费米能级，我们发现多数电子和少数电子的寿命几乎相同。这一结果与从头算理论相矛盾，该理论预测三维铁磁体中大多数电子的寿命将延长5到10倍。我们提供了直接的实验证据，证明这种差异是由交换散射在非弹性电子衰变中的主导地位以及二次电子的激发引起的。后者是所有真实材料和设备所固有的。
The spin-dependent lifetimes of hot electrons in fcc Co films were studied by spin-and time-resolved two-photon photoemission. Even for excitation energies close to the Fermi level, we find almost identical lifetimes for majority and minority electrons. This result contradicts ab initio theories predicting 5 to 10 times longer lifetimes for the majority electrons in 3d ferromagnets. We provide direct experimental evidence that this discrepancy is caused by the dominance of exchange scattering in inelastic electron decay, in combination with the excitation of secondary electrons. The latter are inherent for all real materials and devices.