Studies of the not so Simple Alkali Metals

9814260伯格曼凝聚态物理项目研究了通常被认为是近自由电子系统最简单例子的磁阻和正常电输运，碱金属，锂，钠，钾，铷和铯。然而，最近的实验薄碱膜显示非常不寻常的行为，这不能解释在近自由电子模型。这项研究将调查这种行为的起源，在薄膜中的杂质覆盖率为1/100的单层，其中观察到电阻和负霍尔常数的显着增加。还将研究低于20 K的钾膜的反常磁阻。低覆盖率的这些电影与铅也导致行为不容易理解与传统的弱本地化理论。还确定了其他异常并将其作为研究目标。这项研究特别适合研究生和本科生教育，因为它提供了基础物理和应用物理的培训。碱金属锂、钠、钾、铷和铯通常被认为是元素周期表中最简单的金属。然而，由A. W.大约30年前，奥弗豪泽预言了碱金属的一种非常复杂的结构。这个凝聚态物理学项目将调查首席研究员实验室最近的实验，这些实验也指出了碱金属的异常性质。这项工作的重点是金属薄膜。这些薄膜的输运性质，有和没有磁场显示一系列的行为，不同意与传统的理论，可能需要不同的处理，如奥弗豪泽提出的。有趣的是，元素周期表第一行的金属在许多方面都代表着一个未开发的领域。该研究非常适合研究生和本科生教育，因为它提供了基础物理和应用物理方面的培训。学生接受复杂的实验方法的培训，并学习即使是“众所周知的”第一行元素也具有挑战传统理解的新特性。

9814260BergmannThis Condensed Matter Physics project investigates the magneto-resistance and normal electrical transport in what is generally considered the simplest examples of a nearly free electron system, the alkali metals, lithium, sodium, potassium, rubidium and cesium. However, recent experiments on thin alkali films show very unusual behavior, which can not be explained within the nearly free electron model. The research will investigate origins of this behavior in films with impurity coverages of 1/100th of a monolayer, where dramatic increases of resistances and negative Hall constants are observed. The anomalous magneto-resistance of films of potassium below 20 K will also be investigated. Low coverage of these films with lead also leads to behavior not readily understood with conventional theory of weak localization. Additional anomalies are also identified and targeted for study. The research is particularly well suited for graduate and undergraduate education in that it provides training if both fundamental and applied physics. %%% The alkali metals lithium, sodium, potassium, rubidium and cesium are generally considered as the simplest metals in the periodic table. However, a theory developed by A. W. Overhauser some 30 years ago predicts a very complex structure for the alkali metals. This Condensed Matter Physics project will investigate recent experiments in the principal investigator's laboratory that also point to anomalous properties for the alkali metals. The work focuses on thin films of the metals. The transport properties of these films, with and without a magnetic field display a range of behavior that does not agree with the conventional theory and may require a different treatment such as that proposed by Overhauser. It is interesting that the metals in the first row of the periodic table represent in many ways an unexplored territory. The research is very well suited to graduate and undergraduate education in that it provides training in both fundamental and applied physics. The students receive training in sophisticated experimental methods and also learn the even the "well known" first row elements have novel properties that challenge conventional understanding.