EAGER: SUPER: Collaborative Research: Stabilization of Warm and Light Superconductors at Low Pressures by Chemical Doping

该奖项支持计算和实验研究及教育，旨在实现在环境温度和压力下超导材料的合理设计和合成。超导体可以用于许多重要的技术，包括无损耗传输电力的电缆，磁共振成像机和风力涡轮机中的电磁铁，极其敏感的传感器，以及超导计算机中的量子比特。不幸的是，材料中的超导性通常发生在低温下，这是应用的主要障碍。最近的重大突破表明，接近室温的超导体可以用含有轻元素的材料制成，但只有在超过大气压力一百万倍的压力下才能制成。一类已知的高压超导材料是由充满金属原子的氢制成的笼状结构。该团队将基于量子力学进行计算，以确定可以添加到这些笼状结构中的最佳化学物质，从而使它们即使在较低的压力下也能保持良好的超导性能。发现最有前途的掺杂剂的关键将是化学压力图的计算。随后，金刚石砧细胞和大体积压力机将用于合成高质量的晶体选定的化合物，其结构和性质将被实验确定。类似的工作将在由硼和碳原子制成的笼状结构上进行。研究生将接触到一个多学科的氛围，并学习如何与来自不同背景的实验学家和理论家交流。他们将参加外联活动，包括指导本科生，特别是少数民族和代表性不足的群体，以及大学的开放日活动。实验和理论之间的紧密反馈回路将为未来的设计材料研究提供路线图。该奖项支持计算和实验研究和教育，旨在实现在环境温度和压力下超导材料的合理设计和合成。化学压力图的第一性原理计算将用于揭示最有希望的化学掺杂剂，以在低甚至环境压力下稳定的轻元素系统中实现高超导临界温度。这些化合物的压力依赖稳定性、超导性质和光谱特征将被计算，并与化学压力图相关。与此同时，激光加热金刚石砧细胞和大体积压力机内的新途径将用于合成最有前途的高质量晶体。将测量同步加速器单晶x射线衍射、拉曼光谱和输运性质，并与理论结果进行比较，以帮助进行结构、成分和物理性质表征。将测量电导率以验证超导性。该项目将改变基于轻元素的高温超导体的设计、合成和表征方式。pi将重点关注与已知的二元超氢化物相关的化合物，这些化合物含有笼状笼状结构，因为在它们的许多成员中已经测量到了超导性。第一类要研究的是超氢化物的硼/碳类似物，因为用轻p块元素取代氢原子，形成强共价键，将使这些相中的一些在常压下稳定，同时保留对超导性至关重要的性质。第二类是三元超氢化物，由已知的二元化合物衍生而来。化学压力图将揭示哪些元素具有比二元氢化物更密集的正确半径，同时保持大电子声子耦合所需的扩展氢晶格。实验将利用激光加压加热的x射线衍射和拉曼光谱绘制相图。参与该项目的学生将接受最先进的理论和实验技术的培训，并接触到一个多学科的氛围，在那里他们学习与来自不同领域的科学家交流。常温常压超导材料的发明将对电网基础设施、医疗技术、可再生能源产生巨大影响，并带来新的创新。实验与理论之间的紧密反馈回路将推动材料领域的设计发展。pi将与大众科学媒体沟通该领域的突破，从而教育公众并激励未来的科学家。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NONTECHNICAL SUMMARYThis award supports computational and experimental research and education aimed to result in the rational design and synthesis of materials that are superconducting at ambient temperatures and pressures. Superconductors can be used in many important technologies, including cables that transmit power without loss, electromagnets in magnetic resonance imaging machines and wind-turbines, extremely sensitive sensors, and as qubits in superconducting computers. Unfortunately, superconductivity in a material normally takes place at cryogenic temperatures, which is a major hurdle for applications. Recent major breakthroughs have shown that near room temperature superconductors can be made in materials that contain light elements, but only at pressures that surpass one million times atmospheric pressure. One class of known high pressure superconducting materials is based on cage-like structures made from hydrogen that are filled with metal atoms. The team will perform computations based upon quantum mechanics to pinpoint the best chemical species that can be added to these cage-like structures so that they retain their good superconducting properties even at lower pressures. Key to uncovering the most promising dopants will be the calculation of chemical pressure maps. Subsequently, diamond anvil cells and large volume presses will be employed to synthesize high-quality crystals of select compounds whose structures and properties will be experimentally determined. Analogous work will be performed on cage-like structures made from boron and carbon atoms.Graduate students will be exposed to a multi-disciplinary atmosphere, and learn how to communicate with experimentalists and theoreticians from different backgrounds. They will participate in outreach activities including mentoring undergraduates, especially from minority and underrepresented groups, and university open house events. The tight feedback loop between experiment and theory will provide a roadmap for future materials-by-design research.TECHNICAL SUMMARYThis award supports computational and experimental research and education aimed to result in the rational design and synthesis of materials that are superconducting at ambient temperatures and pressures. First-principles calculations of chemical pressure maps will be used to uncover the most promising chemical dopants for achieving high superconducting critical temperatures in light element systems stable at low, and even ambient pressures. The pressure-dependent stability, superconducting properties and spectroscopic signatures of these compounds will be calculated, and related to the chemical pressure maps. At the same time, novel pathways within laser heated diamond anvil cells and large volume presses will be used to synthesize high-quality crystals of the most promising candidates. Synchrotron single-crystal x-ray diffraction, Raman spectroscopy and transport properties will be measured, and compared with theoretical results to aid in structural, compositional, and physical property characterization. Electrical conductivity will be measured to verify superconductivity. This project will transform the way in which light element based high-temperature superconductors are designed, synthesized, and characterized.The PIs will focus on compounds related to the known binary superhydrides that contain clathrate cage-like structures because superconductivity has been measured in many of their members. The first class to be studied are boron/carbon analogues of the superhydrides because the replacement of the hydrogen atoms by light p-block elements that form strong covalent bonds will render some of these phases stable at normal pressures while retaining properties that are crucial for superconductivity. The second class are ternary superhydrides derived from the known binaries. Chemical pressure maps will reveal which elements have the correct radius to achieve a denser packing than in the binary hydride, while at the same time keeping the extended hydrogenic lattice required for the large electron phonon coupling. Experiments will map out the phase diagram by x-ray diffraction and Raman with laser heating under pressure.Students involved in this project will be trained in state-of-the-art theoretical and experimental techniques, and be exposed to a multi-disciplinary atmosphere where they learn to communicate with scientists from very different fields. The creation of materials that are superconducting at normal temperatures and pressures will have a tremendous impact on the electrical grid infrastructure, medical technology, renewable energy and lead to new innovations. The tight feedback loop between experiment and theory will advance the field of materials by design. The PIs will communicate with the popular science media about the breakthroughs made in this field, thereby educating the public and motivating future scientists.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.