Spin-Orbit and Magnetic Scattering and Non-Equilibrium Properties by Weak Localization

利用金属薄膜中电子的弱局域化来观察自旋轨道和磁性电子-杂质原子相互作用引起的杂质原子的电子散射。作为外加磁场的函数测量的输运数据可以解释为产生有关杂质原子的电子结构的信息。对s和p杂质的早期研究正在扩展和扩展到包括d杂质。另一个子项目将研究在高电流密度影响下的薄膜。这对应于电子温度远高于声子温度的稳定非平衡态。这样的测量可以得到有关电子-声子系统、电子-声子相互作用和薄膜与衬底之间的卡皮察电阻的信息。由于量子效应，金属中的电子同时具有粒子和波的性质。在低温下，电子波在较长的距离上是相干的，并影响金属的性质。特别是，由于电子波可以相互干扰，诸如电阻之类的输运性质被改变。外部磁场改变了电子波的相位并改变了干扰。因此，电阻取决于磁场。（由于历史原因，这种现象被称为弱局部化）。对磁电阻的仔细分析揭示了电子命运随时间变化的详细信息。例如，我们可以在非常短的皮秒（百万分之一秒的百万分之一）的时间尺度上确定电子自旋的旋转作为时间的函数。这种旋转发生在电子遇到杂质时，称为自旋轨道散射。对宿主金属镁中各种杂质原子（铜、锌、金、锡等）的散射进行了研究。这项研究提供了关于金属和合金的磁性和电子特性的重要信息，并将有助于开发具有有用特性的新材料，特别是在低温下。

Weak localization of electrons in thin metal films is used to observe electron scattering from impurity atoms arising from spin- orbit and magnetic electron-impurity atom interactions. Transport data measured as a function of an applied magnetic field can be interpreted to yield information about the electronic structure of the impurity atoms. Earlier research on s and p impurities is being expended and extended to include d impurities. An additional subproject will investigate thin films under the influence of a high current density. This corresponds to a steady non-equilibrium state with the electron temperature considerably above the phonon temperature. Such measurements yield information about the electron-phonon system, the electron-phonon interaction and the Kapitza resistance between film and the substrate. %%% Because of quantum effects, electrons in metals display both particle and wave properties. At low temperatures, the electron waves are coherent over extended distances and influence the properties of the metal. In particular, the transport properties such as the resistance are modified because the electron waves can interfere with each other. An external magnetic field alters the phase of the electron waves and modifies the interference. As a consequence the resistance depends on the magnetic field. (For historical reasons, this phenomena is called weak localization). A careful analysis of the magneto-resistance reveals detailed information about the fate of the electrons as a function of time. For example, we can determine the rotation of the electron spin as a function of time on the very short time scale of pico-seconds (one millionth of a millionth of a second). Such a rotation occurs when the electron encounters impurities and is called spin-orbit scattering. This scattering is being studied for various impurity atoms (copper, zinc, gold, tin, etc.) in host magnesium metal. The research provides important information about the magnetic and electronic properties of metals and alloys and will aid in the development of new materials with useful properties, particularly at low temperatures.