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

点击翻译按钮获取中文摘要

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.