EAGER: SUPER: Alkane-based molecular synthesis and quantum sensing of light & warm superconductors

非技术概述超导体有可能改变我们社会未来的运输和配电网络，因为它具有独特的导电能力，不会因电阻而产生损耗。磁悬浮列车可以在没有摩擦的情况下高效地运送乘客和货物。超导输电线路有助于降低发达工业化经济体的整体碳预算。通常情况下，材料只有在远低于水的冰点的低温下才会表现出超导行为。超导领域的一个重大挑战是发现在室温下具有超导性能的材料。在过去的十年里，在证明金属和非金属材料在压缩到10万大气压数量级时可以表现出高温(~300K)超导电性方面取得了巨大的进展。在材料研究部的支持下，华盛顿大学的Peter Pauzoskie教授和他的研究小组将开发新的化学材料合成和加工方法，以制造非金属元素(碳、氢、硫)的高温超导体，同时还可以保持其在大气压下的超导性能。材料的合成将基于分子烷烃前驱体的使用，这些分子烷烃前体暴露在钻石顶压室内的高压下。钻石顶锤中的氮杂质将被用来根据光学检测到的磁共振检测到超导状态的转变。高压回收材料的原子微结构将用同位素灵敏显微镜进行表征。技术综述在过去的10年里，基于二元金属氢化物和三元非金属氢化材料的高压材料的发现取得了巨大的进步，这些材料在温温下表现出超导相变。如果观察超导所需的压力可以降低到大气压，那么这些材料将有可能彻底改变美国的公共交通网络、国家的电力配电网，以及基于同步加速器的国家科学用户设施。目前还没有基本的科学知识来实现能够在1)室温和2)大气压下演示超导电性的材料。最近，氢化碳硫化物(HCS)材料在高压下的室温超导电性被报道，然而这些材料的原子微结构仍然是一个谜。这个由材料研究部支持的项目将测试高风险、高回报的假设，即饱和分子烷烃(CnX2n+2，X=H，D)可以用来制造低成本的HCS室温超导体，而不需要分子氢。将在实验中得到验证的中心假设是，分子材料可以作为氢源，通过在高表面积、含碳的起始材料中进行原子精确的氢掺杂，在大气压下形成氢-碳-硫室温超导体。这一假设将通过独特的实验设计得到验证，该设计基于1)原子精确的、基于分子烷烃的氢气输送，2)高压高温材料合成，3)基于光学检测磁共振的超导相变的原位量子传感，以及4)用于对回收的产品材料进行定量微结构表征的非原位原子探针断层扫描。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical SummarySuperconductors have the potential to transform our society’s future transportation and electricity distribution networks based on their unique ability to conduct electricity without loss due to electrical resistance. Magnetically-levitated trains could transport passengers and cargo efficiently without friction. Superconducting power transmission lines could help lower the overall carbon budgets of advanced, industrialized economies. Normally, materials show superconducting behavior only at low temperatures, well below the freezing point of water. One grand challenge in the field of superconductivity is to discover materials that have superconducting properties at room temperature. In the past decade tremendous progress has been made in demonstrating that metallic and non-metallic materials can show superconductivity had high temperatures (~300K) when they are compressed to pressures on the order of 100,000 atmospheres. With this project, supported by Division of Materials Research, Professor Peter Pauzauskie and his research group at the University of Washington will develop new chemical materials synthesis and processing methods to make high-temperature superconductors from non-metallic elements (carbon, hydrogen, sulfur) that could also maintain their superconducting properties at atmospheric pressure. Materials will be synthesized based on the use of molecular alkane precursors exposed to large pressures within a diamond anvil cell. Nitrogen impurities within the diamond anvils will be used to detect the transition to a superconducting state based on optically detected magnetic resonance. The atomic microstructure of the materials recovered from high pressure will be characterized using isotopically sensitive microscopy.Technical SummaryIn the past 10 years tremendous progress has been made in the discovery of materials at high pressure that exhibit a superconducting phase transition at warm temperatures based on binary metal-hydride and ternary non-metallic hydrogenated materials. If the pressure required to observe superconductivity could be lowered to atmospheric pressure, then these materials would have the potential to revolutionize the nation’s public transportation networks, the nation’s electrical energy distribution grid, and also national synchrotron-based scientific user facilities. Currently there is no fundamental scientific knowledge to realize materials capable of demonstrating superconductivity at both 1) room temperature and 2) atmospheric pressure. Recently room-temperature superconductivity has been reported at high (GPa) pressures for hydrogenated carbon sulfide (HCS) materials, however the atomistic microstructure of these materials remains a mystery. This project, supported by the Division of Materials Research, will test the high-risk, high-reward hypothesis that saturated molecular alkanes (CnX2n+2, X = H, D) can be used to create low-cost HCS room temperature superconductors without the need for molecular hydrogen. The central hypothesis that will be tested experimentally is that molecular materials can serve as a hydrogen source that will enable the formation of hydrogen-carbon-sulfur room temperature superconductors at atmospheric pressure through the atomically precise doping of hydrogen within high-surface-area, carbonaceous starting materials. This hypothesis will be tested with a unique experimental design based on 1) atomically precise, molecular alkane-based delivery of hydrogen, 2) high-pressure, high-temperature materials synthesis, 3) in situ quantum sensing of superconducting phase transitions based on optically detected magnetic resonance, and 4) ex situ atom probe tomography for quantitative microstructural characterization of recovered product materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.