Investigation of Nanoscale Electronic Properties and Transport in Semiconductors and Magnetic Materials

本项目致力于研究III-V氮化物异质结构和磁性材料中的自旋相关输运。该方法使用近端探头(扫描电容和隧道显微镜)以及导电近端探头来执行局部光导测量，以表征半导体和磁性材料中的局部电子结构和电荷传输特性。目的是加深对缺陷和其他结构特征对材料性能和器件性能的性质和影响的了解，为各种器件应用的材料质量优化和外延层设计提供参考。磁性薄膜材料的研究将集中在自旋极化电流-电压和电导光谱的发展和应用，并结合原子力显微镜和磁力显微镜来表征磁性薄膜材料中的自旋极化电流注入和自旋相关的载流子输运。这种方法可以在几十纳米的长度尺度上研究各种现象，如自旋极化电流注入各种磁性和磁阻薄膜材料，自旋相关的载流子在单个磁畴壁上的传输，以及铁磁-绝缘体-铁磁隧道结中自旋相关的隧道过程的详细性质。%该项目解决材料科学中具有高度技术相关性的专题领域的基础研究问题。将高度重视对研究生进行先进的纳米表征技术的培训，这些技术在现代材料和设备工程中越来越重要。此外，还将强调基本材料特性的研究及其在设备工程和应用中的作用之间的联系，从而为学生提供与相关领域的其他大学和工业研究人员互动的机会。

This project addresses research centered on III-V nitride heterostructures and spin-dependent transport in magnetic materials. The approach employs proximal probes(scanning capacitance and tunneling microscopies), as well as a conducting proximal probe tip to perform local photoconductivity measurements for characterization of local electronic structure and charge transport properties in semiconductor and magnetic materials. The aim is to increase understanding of the nature and influence of defects and other structural features on material properties and device performance, serving to inform strategies for optimization of material quality and epitaxial layer design for a variety of device applications. Investigation of magnetic thin-film materials will focus on the development and application of spin-polarized current-voltage and conductance spectroscopy in combination with atomic and magnetic force microscopy to characterize spin-polarized current injection and spin-dependent carrier transport in magnetic thin-film materials. The approach allows studies at lengths scales as small as a few tens of nm of phenomena such as spin-polarized current injection into a variety of magnetic and magnetoresistive thin-film materials, spin-dependent carrier transport across single magnetic domain walls, and the detailed nature of spin-dependent tunneling processes in ferromagnet-insulator-ferromagnet tunnel junctions. %%%The project addresses basic research issues in topical areas of materials science with high technological relevance. High priority will be placed on training of graduate students in advanced nano-characterization techniques of increasing importance in modern materials and device engineering. In addition, the connection between studies of basic material properties and their role in device engineering and applications will be emphasized, thereby affording students opportunities for interaction with other university and industrial researchers working in related areas.***