Excellence in Research: Understanding Structural, Magnetic, and Electronic Properties of Chromium Telluride

近年来，人们对绿色技术越来越感兴趣，这种技术可以降低对不可再生能源的依赖，从而减少它们对环境的影响。磁热材料是在这一奋进中正在探索的一类重要材料。这些材料在固态制冷、微制冷、能量转换、磁泵、诱导磁热疗和药物控释等方面具有潜在的应用前景。在这个项目中，我们研究了一种室温磁热材料，碲化铬，以了解其磁性，电子和结构特性之间的关系。这项研究是在霍华德大学与国家实验室合作进行的，这使霍华德大学的研究人员能够与外部社区建立密切的研究合作。霍华德大学是最大的研究活跃的历史上黑人大学（HBCU），有大量的历史上代表性不足的学生人口。因此，这项研究为代表性不足的少数民族学生带来了前沿研究机会，并扩大了他们对材料科学研究的参与。这些研究人员正在接受高级材料科学研究，数据分析，模拟，科学写作和演讲技巧的培训。这将提高他们在学术界和工业界与潜在雇主的竞争力。近年来，铬硫族化合物由于其多样的磁性而引起了人们极大的兴趣。本计画以室温磁性材料碲化铬为研究对象，以了解其结构、磁性与电子性质之间的关系。该研究包括单晶生长，磁性，热容，磁输运，同步加速器X射线散射和中子衍射研究，所有这些都由基于密度泛函理论（DFT）的模拟补充。对分布函数的研究，以确定碲化铬结构随温度的演变。相干软x射线光谱研究有助于确定其基态电子结构。此外，中子衍射研究有助于确定其磁序。该项目有助于回答与其磁结构相变相关的未解决的基本问题。此外，该材料被用于探索平行反常霍尔效应（PAHE）。因此，这项拟议中的研究与霍华德前瞻战略保持一致，即为代表性不足的少数民族学生提供卓越的教育和研究经验，并吸引来自这些群体的下一代STEM学者。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响力审查标准进行评估来支持。

Non-technical AbstractIn recent years, there has been an increased interest in green technologies, which can lower the dependence on non-renewable sources of energy, thus reducing their environmental impacts. Magneto-caloric materials are an important class of materials being explored in this endeavor. These materials have potential applications in solid-state refrigeration, micro-coolers, energy conversion, magnetic pump, induced magnetic hyperthermia, and controlled drug delivery. In this project, we study a room temperature magneto-caloric material, chromium telluride, to understand the relationship between its magnetic, electronic and structural properties. The research is performed at Howard University in collaboration with national laboratories, which enables Howard University researchers to forge close research collaborations with outside communities. Howard University is the largest research-active historically black university (HBCU), with a large historically underrepresented student population. Therefore, this research is bringing cutting-edge research opportunities to underrepresented minority students and is broadening their participation in materials science research. These researchers are being trained in advanced material science research, data analysis, simulations, scientific writing, and presentation skills. This will enhance their competitiveness with prospective employers both in academia and industry. Technical AbstractRecently, chromium chalcogenides have drawn much interest due to their diverse magnetic properties. This project studies one room-temperature magnetic material, chromium telluride, to understand the relation between its structural, magnetic, and electronic properties. The research includes single crystal growth, magnetic, heat capacity, magneto-transport, synchrotron x-ray scattering, and neutron diffraction studies, all supplemented by density functional theory (DFT)-based simulations. Pair distribution function studies are performed to determine the evolution of the chromium telluride structure with temperature. Coherent soft x-ray spectroscopy studies help determine its ground-state electronic structure. Furthermore, neutron diffraction studies help determine its magnetic ordering. This project helps answer unaddressed fundamental questions associated with its magneto-structural phase transitions. In addition, this material is used to explore the parallel anomalous Hall effect (PAHE). Therefore, this proposed research aligns well with the Howard Forward strategy of providing underrepresented minority students with exceptional educational and research experiences and attracting next-generation STEM scholars from such groups.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.