Understanding Electronic and Magnetic Interactions in Complex Mixed Metal Chalcogenides

非技术摘要创造新的磁性半导体的能力，其中导电电子的“上”或“下”磁自旋取向可以通过在环境温度下的“开”或“关”电荷来控制和操纵，这可能导致更小的基于自旋的电子(自旋电子学)，用于更快的数据处理、超高密度的数据存储和低功耗。在固态和材料化学计划的支持下，研究小组将使用实验和计算技术相结合的方法来创造具有灵活晶体结构的新型铁磁半导体，并研究这些化合物中自由载流子的磁自旋和局域磁原子之间相互作用的性质，从而使室温下具有稳定的自旋电子性能。这类化合物的发现可能为下一代计算铺平道路，在下一代计算中，数据存储和处理功能集成在单一芯片上。该项目的多学科性质使研究生、本科生实习生、高中生和高中教师得到了出色的培训。技术摘要设计无机半导体的原子结构以创建嵌入在半导体晶格中的孤立的一维铁磁亚单位可以实现(1)对单个磁区内的铁磁耦合强度的电子操纵和(2)对半导体框架内的电子传输的磁控制。这种在同一晶体结构中有序磁区和半导体区的原子尺度集成使得能够独立地研究和理解这些新型铁磁半导体(FMS)中自由载流子自旋和局域磁矩之间的相互作用。在这个项目中，研究小组将先进的生长和表征技术与第一性原理计算相结合，研究基于过渡金属硫族化合物的FMS。其目的是阐明电荷载流子在嵌入同一晶格的局域磁性亚结构之间的耦合机制，以便在单一材料中实现诸如大磁矩、大矫直力、高居里温度和高电导率的奇异组合。这一结果将极大地提高我们对电子性质与磁性耦合本质的认识，这对进一步扩展自旋电子材料的研究具有重要意义。

Non-technical AbstractThe ability to create new magnetic semiconductors in which the "up" or "down" magnetic spin orientation of conducting electrons can be controlled and manipulated through "on" or "off" electrical charge at ambient temperature could lead to smaller spin-based electronics (spintronics) for faster data processing, ultra-high-density data storage and low power consumption. With the support of the Solid State and Materials Chemistry program, the research team will use a combination of experimental and computational techniques to create new ferromagnetic semiconductors with flexible crystal structure and to investigate the nature of interactions between magnetic spin of free-carriers and localized magnetic atoms within these compounds that enables stable spintronic properties at room temperature. The discovery of such compounds could pave the way to next-generation computing in which data storage and processing functionalities are integrated on a single chip. The multidisciplinary nature of this project enables outstanding training of graduate students, undergraduate interns, high-school students and high-school teachers. Technical AbstractEngineering the atomic structure of an inorganic semiconductor to create isolated one-dimensional ferromagnetic subunits embedded within the semiconducting crystal lattice can enable (1) electronic manipulation of the ferromagnetic coupling strength within individual magnetic domains and (2) magnetic control of electronic transport within the semiconducting framework. Such atomic-scale integration of ordered magnetic and semiconducting domains in the same crystal structure enables independent investigation and understanding of the interactions between free-carrier spins and localized magnetic moments within these new classes of ferromagnetic semiconductors (FMSs). In this project, the research team combines advanced growth and characterization techniques with first-principles calculations to investigate FMSs based on transition-metal chalcogenides. The goal is to elucidate the mechanism by which charge carriers mediate or induce coupling between localized magnetic substructures embedded in the same crystal lattice in order to achieve exotic combinations of properties such as large magnetic moments, large coercivity, high Curie temperature and high electrical conductivity within a single material. Such a result would significantly advance our knowledge about the nature of coupling between electronic properties and magnetism, which is of tremendous importance to further expansion of research on spintronic materials.