Institut für Experimentalphysik, Universität Hamburg and Centre for Free-Electron Laser Science, Hamburg, Germany.
Phys Rev Lett. 2009 Dec 4;103(23):237401. doi: 10.1103/PhysRevLett.103.237401. Epub 2009 Dec 2.
Experimentally, we observe angular-momentum transfer in electron-phonon scattering, although it is commonly agreed that phonons transfer mostly linear momentum. Therefore, the incorporation of angular momentum to describe phonons is necessary already for simple semiconductors and bears significant implications for the formation of new quasiparticles in correlated functional materials. Separation of linear and angular-momentum transfer in electron-phonon scattering is achieved by highly selective excitations on the femtosecond time scale of resonant inelastic x-ray scattering.
在实验中，我们观察到电子-声子散射中的角动量转移，尽管人们普遍认为声子主要传递线性动量。因此，即使是对于简单的半导体，用角动量来描述声子也是必要的，这对于关联功能材料中新型准粒子的形成具有重要意义。通过共振非弹性 X 射线散射的飞秒时间尺度上的高选择性激发，可以实现电子-声子散射中线性和角动量转移的分离。
