Studies of Spin-Currents, Anomalous Hall Effect and Ballistic Electron Propagation in Quench Condensed Alkali Films

这个个人研究人员奖是为了研究碱金属薄膜的性质，这些薄膜在与其他材料接触时会发生改变。碱金属具有独特的性质，即使在淬火凝聚的薄膜中，传导电子也具有长的平均自由程。通过淬火凝聚，可以制备复杂的三明治，并可以在现场研究传导电子的弹道传播。与Fe膜弱接触的碱性膜表现出较强的自旋流。研究的重点之一是自旋流和反常霍尔效应的研究。由于这两种现象在自旋电子学领域的重要性，近年来引起了人们的浓厚兴趣。此外，碱金属薄膜在存储超极化惰性气体(用于肺部核磁共振)方面也有重要的应用。只有用碱性薄膜覆盖的容器才能将超极化惰性气体储存足够长的时间，其原因目前尚不清楚。该项目向研究生和本科生介绍高真空、低温和薄膜物理技术。在全校本科生科研竞赛中，曾参加过校长课题组研究项目的本科生获得了一等奖和二等奖。最近，碱金属薄膜在肺部和其他充气器官的磁共振医学应用中变得重要起来。对于肺部的核磁共振成像，需要超极化的稀有气体(例如HE3)。只有用碱性薄膜覆盖的容器才能将这些气体储存足够长的时间。目前，实现这一目标的碱金属性质尚不清楚。在拟议的项目中，将研究碱性薄膜与其他材料接触时的改性性能。碱性薄膜具有独特的性质，即使当它们凝聚在液氦冷却的衬底上时，它们也能形成相当完美的晶格。因此，可以研究导电电子在碱和其他金属的复合多层膜中的弹道传播。该项目的重点是研究铁碱多层膜中的自旋流和碱性薄膜与其他材料的接触特性。该项目向研究生和本科生介绍高真空、低温和薄膜物理技术，并将他们培养为前沿科学研究的合格工作者。在全校本科生科研竞赛中，曾参加过校长课题组研究项目的本科生获得了一等奖和二等奖。

This individual investigator award is to study the properties of alkali metal films that get modified when they are in contact with other materials. Alkali metals have the unique property that even in quench-condensed films the conduction electrons have long mean free paths. With quenched condensation, complex sandwiches can be prepared and the ballistic propagation of conduction electrons can be investigated in situ. Alkali films in weak contact with Fe films show strong spin currents. One focus of the proposed research is the study of spin currents and the anomalous Hall effect. Both phenomena have attracted strong interest in recent years because of their importance in the field of spintronics. Furthermore, alkali metal films have found important applications in the storage of hyperpolarized noble gases (which are used in MRI of the lungs). Only containers covered with alkali films can store the hyperpolarized noble gases over a sufficiently long time and the cause of it is not understood at present. The project introduces graduate and undergraduate students to the techniques of high vacuum, low temperature, and thin film physics. Undergraduate students who participated in previous research projects in the principal investigator's group have won first and second prizes in university-wide undergraduate research competition. Films of alkali metals became recently important in the medical application of MRI to the lungs and other air filled organs. For the MRI of the lungs, one needs hyperpolarized noble gases (for example He3). Only containers covered with alkali films can store these gases for sufficiently long times. The property of alkali metals that makes this possible is not clear at present. Within the proposed project, the modified properties of alkali films when in contact with other material will be investigated. Alkali films have the unique property that they form a rather perfect lattice even when they are condensed onto a liquid-helium-cooled substrate. Therefore, the ballistic propagation of conduction electrons can be investigated in complex multi-films of alkali and other metals. The project focuses on the investigation of spin currents in iron-alkali multi-films and the properties of thin alkali films in contact with other materials.The project introduces graduate and undergraduate students to the techniques of high vacuum, low temperature, and thin film physics and trains them as competent workers for frontier scientific research. Undergraduate students who participated in previous research projects in the principal investigator's group have won first and second prizes in university-wide undergraduate research competition.