Studying novel materials using synchrotron-based spectroscopy and density functional calculations

物质的外层电子和不太强的电子负责大多数材料的性质，包括颜色、化学键、原子和电子结构、磁性、带隙、导电性和热导性，甚至超导性。拥有测量、建模和了解材料外部电子的手段是了解和调整重要物理性质的关键。这项研究将在该小组自己位于加拿大光源的终端站使用基于同步加速器的软X射线光谱学，在三个重点领域回答有关新材料结构的关键问题：1.空位在自旋电子和其他材料中的作用，用于新的存储设备和高性能计算：空位在凝聚态物理中很重要，但出了名的难以检测。我们首创了一种可以研究职位空缺的方法。我们专门研究了它们在使用电子自旋和电荷存储信息的新型铁磁半导体中的作用。如果大规模实现，自旋电子学将允许更快的处理速度、更高的存储密度和更低的能源消耗，从而彻底改变计算能力。2.LED照明应用的新材料：我们重点研究了一系列新一代稀土掺杂氮化物荧光粉的电子结构的详细表征和发展。这些窄带发射、高效的荧光粉已显示出在荧光粉转换发光二极管(PC-LED)中的巨大潜力，这是一项有望取代传统白炽灯的技术。预计它们将使全球能源消耗显著减少15%，长期降幅要大得多。这种能源消耗的减少将受到新型高效荧光粉开发的推动。3.低维材料：本项目的第一个目标是阐明一维线性碳链的基本物理和电学性质，以及衬底的选择、碳链长度和掺杂剂的引入对电子性质的影响。在扩展到二维材料方面，我们将研究单层材料磷烯和硼烯，试图建立在强度和电荷迁移率方面具有独特性能的独立单层膜，这些特性是基本感兴趣的，并在许多领域适用。总体而言，将我们的同步加速器测量与最先进的理论计算进行比较，将提供非常详细的洞察力，并有助于设计具有定制的电子、光学、磁性和化学性质的新材料，用于能耗低得多的照明应用和电子应用，以实现更快、更节能的计算，从而允许处理更大的数据集。

The outer and less strongly bound electrons of matter are responsible for most material properties including color, chemical bonding, atomic and electronic structure, magnetism, band gap, electrical and heat conductivity, and even super-conductivity. Having the means to measure, model, and understand the outer electrons of a material is the key to understanding and tailoring important physical properties. This research will employ synchrotron-based soft X-ray spectroscopy at the group's own endstation at the Canadian Light Source to answer key questions concerning the structure of new materials in three areas of focus: 1. The role of vacancies in spinelectronic and other materials for new storage devices and high performance computing: Vacancies are important in condensed matter physics but notoriously difficult to detect. We have pioneered a method that allows studying vacancies. We specifically study their role in new ferromagnetic semiconductors for applications that use the electron spin and charge to store information. If realized on a large scale, spintronics will revolutionize computing capabilities by allowing faster processing speed, higher storage density and less energy consumption. 2. New materials for LED lighting applications: We focus on the detailed characterization and development of the electronic structures of a series of next-generation, rare earth-doped, nitride phosphors. These narrow-band-emitting, high-efficiency phosphors have demonstrated outstanding potential for use in phosphor-converted light emitting diodes (pc-LEDs), a technology poised to replace traditional incandescent lights. They are expected to lead to an outstanding reduction of 15% in global energy consumption with substantially greater long-term reductions. This reduction in energy consumption will be driven by the development of new high-efficiency phosphors. 3. Low dimensional materials: The first goal of this project is to elucidate basic physical and electronic properties of one dimensional, linear carbon chains, as well as how the choice of substrate, carbon chain length and introduction of dopants affects the electronic properties. In the extension to two-dimensional materials, we will study single layered materials phosphorene and borophene in an attempt to establish freestanding monolayers that have unique properties in terms of strength and charge mobility that are of fundamental interest and applicable in many areas. Overall, the comparison of our synchrotron measurements with our state-of-the-art theoretical calculations will provide very detailed insight and facilitate the design of new materials with tailored electronic, optical, magnetic, and chemical properties for use in lighting applications with much less energy consumption and electronics applications for faster and more energy efficient computing allowing handling of larger data sets.