Theoretical and Experimental Studies of Disordered Metallic Systems and Tin-Based Small Gap Semiconductors

这项美国-巴西合作科学奖支持西北大学的Donald Ellis和J.B. Ketterson以及巴西巴西经济研究中心的Elisa Baggio Saitovitch的合作。本项目旨在对分子束外延、电子束外延、电子束外延等可控条件下合成的新型材料进行理论和实验研究。或溅射沉积在晶体基底上。研究人员将测量二元无序金属系统的性质，以确定有序程度、磁性结构和传输参数作为组成、生长条件、层厚度和热处理的函数。他们还将研究异顶稳定薄膜，以开发稳定的小间隙半导体。利用嵌入式簇框架中基于局部密度理论的自洽场模型，他们将在原子水平上探测这些材料的电子结构。聚类计算将用于解释穆斯堡尔、核磁共振、摄动角相关和x射线吸收光谱数据。巴西方面将制作样品，表征材料，并进行光谱测量。美方将提供超精细相互作用和薄膜制备方面的专业知识。

This U.S.-Brazil Cooperative Science award supports the collaboration of Donald Ellis and J.B. Ketterson of Northwestern University and Elisa Baggio Saitovitch of the Centro Brasileiro de Pesquisas Fisicas in Rio de Janeiro, Brazil. The project aims to conduct theoretical and experimental studies of materials with novel properties synthesized under controlled conditions on molecular beam epitaxy, e-beam, or sputter deposition on crystalline substrates. The researchers will measure properties of binary disordered metallic systems to determine the degree of ordering, magnetic structure, and transport parameters as a function of composition, growth conditions, layer thickness, and thermal treatment. They will also study heteropitaxially stabilized films to develop stable small gap semiconductors. Using self-consistent-field models based on Local Density theory in the embedded cluster framework, they will probe the electronic structure of these materials at the atomic level. Cluster calculations will be used to interpret Mossbauer, NMR, Perturbed Angular Correlation, and X-ray absorption spectroscopic data. The Brazilian side will produce specimens, characterize materials, and make spectroscopic measurements. The U.S. side will contribute expertise in hyperfine interactions and preparation of films.