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

在单一材料中开发自旋电子学以及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巨大挑战。这项由固态与材料化学（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属化物的显着结构特征，其一般组成为Pb（n+2）Sb 2（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）来：（i）研究在改变过渡金属元素的性质和/或硫族元素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传输特性如何随着组成和结构的改变而变化;以及（iii）了解电荷载流子浓度和迁移率与结构中磁中心之间耦合之间的相关性。这将通过结合两种方法来实现：（a）给定结构类型内元素的性质和化学计量将系统地变化，并且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，结构密切相关的相（伪同系）将用于研究结构演化（同系内结构类型的变化）对材料的磁性和电荷输运性质的影响。 非技术总结：该研究计划旨在开发单一材料的铁磁和半导体功能。这种材料的可用性可能会影响现代计算机的架构，其中整个计算机构建在单个半导体芯片上，使用能够以电子方式向磁性材料写入信息和从磁性材料阅读信息的设备。此外，这些材料还可以用于构建能够冷却整个计算系统的设备。在这个职业补助金中提出的多成分教育计划将为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接受高温固态合成，X射线衍射和物理性能测量方面的最先进技术的出色培训。他们还将参与数据分析以及准备出版的手稿。虽然新奥尔良大学（UNO）位于一个“城市”，约58%的人口来自非洲裔美国人，但进入高等教育的高中毕业生人数仍然很低。 拟议的社区服务和化学新生计划的学习经验将提供实践经验和培训，目前UNO化学新生，同时激发高中学生（大学生，大三和大四学生）在化学的兴趣。

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.