Temperature Dependent Conduction Studies of Multilayer Material Systems

多层材料中的传导目前引起了人们极大的兴趣，但既没有得到很好的理解，也没有得到详尽的研究。 传导过程的测量是材料科学的基础，因为它相对简单，所以非常适合本科院校的高年级学生。 在这个项目中，低温恒温器集成到现有的电阻率和霍尔效应装置，并用于研究多层材料的电子输运性质的温度依赖性。 该仪器一直在开发中，现在用于初级高级实验室课程，以研究金属和半导体系统。 低温恒温器大大提高了初级实验室课程以及独立研究和高级论文项目的实验能力。 新的项目集中在温度，磁场，电流方向，和多层系统中的磁阻和霍尔电压的层间距的依赖关系。 低温能力允许在足够宽的温度范围内表征输运性质以研究电子散射机制的性质。 研究的初始系统是C/Ge和W/Si多层膜，层厚度范围从5到50埃。 这些多层膜的制造和结构研究是与另一个研究小组合作进行的。 该项目应增加材料科学教育和研究在本科院校的存在。

Conduction in multilayer materials is currently of great interest, but is neither well understood nor has it been exhaustively investigated. Measurement of conduction processes is fundamental in material science, and because it is relatively straightforward it is ideal for upper-level students at undergraduate institutions. In this project, a low-temperature cryostat is integrated into an existing resistivity and Hall effect apparatus and used to study the temperature dependence of the electronic transport properties of multilayer materials. The apparatus has been under development and is now used in a junior- level advanced laboratory course to study metal and semiconductor systems. The cryostat greatly increases the experimental capabilities in the junior-level laboratory course and in independent study and senior-level thesis projects. New projects focus on the temperature, magnetic field, current direction, and layer spacing dependencies of the magnetoresistance and Hall voltage in multilayer systems. Low- temperature capabilities allow the transport properties to be characterized over a temperature range broad enough to study the nature of the electronic scattering mechanisms. Initial systems of study are C/Ge and W/Si multilayers, with layer thicknesses ranging from 5 to 50 Angstroms. Fabrication and structural studies of these multilayers are performed in collaboration with another research group. This project should increase the presence of material science education and research at undergraduate institutions.