CAREER: Understanding and Controlling the Integration of Magnetism into Semiconducting Mixed Metal Chalcogenides

技术概述：在单一材料中开发铁磁性和半导体功能的能力是自旋电子学和热电器件所需要的，这是固态化学中的一个巨大挑战。这项由固态和材料化学（SSMC）计划支持的CAREER资助旨在利用合成和天然存在的三元和四元重主族金属硫族化合物的显著结构特征，其一般组成为Pb(n+2)Sb2(m+1)Q（n+3m+5）和MtPb(n-t+2)Sb2(m+1)Q(n+3m+5) (m = Mn, Fe, Co; Q = S, Se, Te)，以：(i)研究改变过渡金属元素的性质和/或碳原子的性质时框架结构的稳定性；（ii）研究这类化合物的磁性和电荷输运性质如何随其组成和结构的改变而改变；(3)了解载流子浓度与迁移率之间的关系以及结构中磁中心之间的耦合。这将通过结合两种方法来完成：(a)给定结构类型中的元素的性质和化学计量学将会系统地变化，并将评估它们对所得材料的磁性和电子输运的影响；(b)对于给定系统；结构紧密相关的相（拟同源序列）将用于研究结构演化（同源序列内结构类型的变化）对材料磁性和电荷输运性质的影响。非技术总结：本研究计划旨在开发单一材料的铁磁性和半导体功能。这种材料的可用性可能会影响现代计算机的结构，在现代计算机中，整个计算机是建立在单个半导体芯片上的，使用能够从磁性材料中电子地读写信息的设备。此外，这些材料还可以用来制造一种能够冷却整个计算系统的设备。该职业基金提出的多组件教育计划将为K-12教师、高中生、本科生、研究生和博士后提供研究和教学经验。研究生和博士后研究人员将在高温固体合成、x射线衍射和物理性质测量方面接受先进技术的优秀培训。他们还将参与数据分析以及编写供出版的手稿。尽管新奥尔良大学（UNO）位于一个“城市”，其中约58%的人口来自非洲裔美国人，但这一群体进入高等教育的高中毕业生数量仍然很低。拟议的社区服务和化学新生学习经验计划将为当前UNO化学新生提供实践经验和培训，同时激发高中学生（二年级，三年级和四年级）对化学的兴趣。

TECHNICAL SUMMARY:The ability to develop in a single material, ferromagnetic and semiconducting functionalities which are desirable for spintronics as well as thermoelectric devices is a great challenge in solid state chemistry. This CAREER grant supported by the Solid State and Materials Chemistry (SSMC) program seeks to exploit the marked structural features of synthetic and naturally occurring ternary and quaternary heavy main-group metal chalcogenides with general composition Pb(n+2)Sb2(m+1)Q(n+3m+5 and MtPb(n-t+2)Sb2(m+1)Q(n+3m+5) (M = Mn, Fe, Co; Q = S, Se, Te) to: (i) investigate the stability of the framework structure upon changing the nature of transition metal elements and/or the nature of chalcogen atom; (ii) investigate how the magnetism and the charge transport properties of this family of compounds change with modification of the composition and structure; and (iii) understand the correlation between the charge carrier's concentration and mobility and the coupling between magnetic centers in the structure. This will be done by combining two approaches: (a) the nature and stoichiometry of elements within a given structure type will be systematically varied and their effects on the magnetism and electronic transport of the resulting materials will be assessed, (b) for a given system, phases with structures closely related to each other (pseudo-homologous series) will be used to investigate the effects of structural evolution (changes in structure type within the homologous series) on the magnetism and charge transport properties of the materials. NON-TECHNICAL SUMMARY:This research program aims to develop ferromagnetic and semiconducting functionalities in a single material. The availability of such materials could impact the architecture of modern computers where an entire computer is built on a single semiconducting chip using a device capable of electronically writing and reading information to and from a magnetic material. Additionally, the materials can also be used to build a device capable of cooling the whole computing system. The multi-component educational program proposed in this CAREER grant will provide research and teaching experiences to K-12 teachers, high school students, undergraduate students, graduate students and postdoctoral associates. Graduate students and postdoctoral researchers will receive outstanding training on state-of-the-art techniques in high temperature solid-state synthesis, X-ray diffraction and physical properties measurements. They will also be involved in data analysis as well as preparation of manuscripts for publication. Although, the University of New Orleans (UNO) is located in an "urban city" with about 58% of the population from African American origin, the number of high school seniors from this group entering higher education is still low. The proposed Community Services and Learning Experiences for Chemistry Freshmen program will provide hands-on experience and training to current UNO Chemistry freshmen while simultaneously stimulating interest among high school students (sophomores, juniors and seniors) in chemistry.