Novel Hydrogen-rich Materials at High Pressures: Possible Route to Room Temperature Superconductivity

非技术摘要：超导体在没有电阻的情况下导电，是凝聚态物理学中最吸引人的材料之一。在室温或接近室温时实现超导状态将彻底改变我们的能源生产和运输系统，并将促进经济增长和生活质量。压力已被证明是制造具有奇异性质(如超导电性)的新型材料的最通用的调谐参数。固态金属氢是氢的高压相，被预测具有室温超导电性。然而，这需要极端的压力。富氢材料，模仿难以捉摸的氢的固体金属相，可能会在低得多的压力下导致高T_c超导。该项目的主要目标是在高压高温条件下合成新型的富氢超导材料，并探索其可能的室温超导电性。这个项目的进展可以提供更多关于超导机制的清楚信息。反过来，它可能会让我们深入了解在常压下大量设计新的超导材料。通过一种全面的外展方式，首席调查员将招募和指导高中生，提供经验，培养他们的科学探究和沟通技能。外展的一个目标是接触到在科学、技术、工程和数学领域代表性不足的学生。首席研究员与罗切斯特大学的麦克奈尔项目合作，该项目的任务是增加攻读博士学位的低收入、第一代和代表性不足的少数族裔本科生的数量。技术摘要：超导一直是凝聚态物理学中最神秘的量子阶段之一。理论上认为，固态金属氢具有高的德拜温度和强的电子-声子耦合，这是高T_c声子介导的超导所必需的。然而，这需要极端的压力。作为另一种选择，富氢材料，模仿难以捉摸的氢的固体金属相，可以在低得多的压力下金属化，在费米水平上提供大的氢导出态电子密度，并响应氢原子的运动(电子-声子耦合)而对电子结构进行大的修改。这项研究的主要目标是合成已知或可能具有高T_c超导电性的新型富氢超导材料。最先进的高压和高温技术、激光光谱学和低温技术与新的输运测量相结合被用于合成和探测高温超导。这个项目的成功阐明了超导机制的更大明确性。反过来，这可能会让研究团队获得在常压下大量设计新超导材料的洞察力。该项目还为研究生提供了尖端纳米制造技术和大型用户设施的实践经验，如同步加速器和中子设施。此外，该项目为当地高中生提供暑期实习机会，首席研究员与罗切斯特大学麦克奈尔项目合作，该项目的使命是增加攻读博士学位的低收入、第一代和代表性不足的少数族裔本科生的数量，以招募和指导学生。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 Abstract: Superconductors, which conduct electricity without resistance, are among the most fascinating materials in condensed matter physics. Achieving a state of superconductivity at room temperature or near room temperature will revolutionize our energy production and transportation system and will enhance economic growth and quality of life. Pressure has been proven to be the most versatile tuning parameter in making novel materials with exotic properties such as superconductivity. Solid metallic hydrogen, the high pressure phase of hydrogen, is predicted to have room temperature superconductivity. However, it requires extreme pressure. Hydrogen-rich materials, mimicking the elusive solid metallic phase of hydrogen, may lead to high-Tc superconductivity at much lower pressures. The primary goal of this project is to synthesize novel hydrogen-rich superconducting materials at high pressure temperature conditions and explore their possible room temperature superconductivity. Progress on this project can provide greater clarity regarding superconducting mechanisms. In turn, it may allow us to obtain insight into designing new superconducting materials in large quantities at ambient pressure. Through a comprehensive outreach approach, the principal investigator will recruit and mentor high school students to provide experiences to foster their scientific inquiry and communication skills. A goal of the outreach is to reach students who are underrepresented in the areas of science, technology, engineering, and mathematics. The principal investigator works with the University of Rochester's McNair program, whose mission is to increase the numbers of low-income, first generation, and underrepresented minority undergraduates who pursue PhD degrees.Technical Abstract: Superconductivity has been one of the most arcane quantum phases in condensed matter physics. Solid metallic hydrogen is theorized to have the high Debye temperature and strong electron-phonon coupling that are necessary for high-Tc phonon-mediated superconductivity. However, it requires extreme pressure. As an alternative, hydrogen-rich materials, mimicking the elusive solid metallic phase of hydrogen, can be metalized at much lower pressures, providing large hydrogen-derived electronic density of states at the Fermi level and large modifications of the electronic structure in response to the motion of hydrogen atoms (electron-phonon coupling). The primary goal of this research is to synthesize novel hydrogen rich superconducting materials that are either known or likely to exhibit high Tc superconductivity. State-of-the-art high pressure and high temperature techniques, laser spectroscopy, and low temperature techniques in conjunction with novel transport measurements are used to synthesize and probe high temperature superconductivity. Success on this project elucidates greater clarity in superconducting mechanisms. In turn, it may allow the research team to obtain insight into designing new superconducting materials in large quantities at ambient pressure. The project also provides graduate students hands-on experience with cutting-edge nano-fabrication technologies and large user facilities, such as synchrotron and neutron facilities. In addition, the project offers summer internships to local high school students, and the principal investigator works with the University of Rochester's McNair program, whose mission is to increase the numbers of low-income, first generation, and underrepresented minority undergraduates who pursue PhD degrees, to recruit and mentor students.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.