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

技术概述：在单一材料中开发自旋电子器件和热电器件所需的铁磁和半导体功能的能力是固态化学中的一个巨大挑战。这项由固态和材料化学(SSMC)计划支持的职业资助旨在开发合成和自然存在的三元和四元重金属主族金属硫化物的显著结构特征，其总组成为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/或硫原子的性质时骨架结构的稳定性；(Ii)研究这类化合物的磁性和电荷输运性质是如何随着组成和结构的改变而变化的；以及(Iii)了解电荷载流子浓度和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)给定结构类型内的元素的性质和化学计量将被系统地改变，并将评估它们对所产生的材料的磁性和电子传输的影响，(B)对于给定的系统，结构彼此密切相关的相(伪同源系列)将被用来研究结构演变(同源系列中的结构类型的变化)对材料的磁性和电荷传输性能的影响。非技术概述：这项研究计划旨在开发单一材料的铁磁性和半导体功能。这种材料的可获得性可能会影响现代计算机的体系结构，在现代计算机中，整个计算机建立在单个半导体芯片上，使用能够对磁性材料进行电子写入和读取信息的设备。此外，这种材料还可以用来建造一种能够冷却整个计算机系统的设备。这项职业助学金中提出的多元教育计划将为K-12教师、高中生、本科生、研究生和博士后助理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态合成、X射线衍射和物理性能测量方面接受最先进的技术培训。他们还将参与数据分析以及准备出版手稿。尽管新奥尔良大学(UNO)位于一座人口约58%来自非裔美国人的“城市城市”，但这一群体的高三学生进入高等教育的人数仍然很低。拟议的化学新生社区服务和学习体验计划将为目前的联合国大学化学新生提供实践经验和培训，同时激发高中生(大二、大三和大四)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.