Theoretical Investigation of Quantum Materials: Superconductors, Dirac-Weyl Semimetals and other Graphene-like Materials

量子材料对我们现代世界的技术是必不可少的。这项研究计划涉及量子材料研究的两个主要领域。其一是发现和理解在接近室温下工作的超导体的潜力。超导体目前被用于医院的核磁共振机器，并正在开发用于电力传输电缆和磁悬浮高速列车等应用。当前一代材料只能在零下270摄氏度附近的非常低的温度下工作，需要昂贵的液氦，而液氦的供应也是有限的。随着接近室温的超导体的发现，可能会出现巨大的改进，这种超导体几乎不需要冷却。我们正在研究材料中可能产生这种可能性的机制。第二个方向是对所谓的狄拉克-韦尔材料的调查。最近发现的这类材料(单层碳原子石墨烯就是一个突出的例子)推动了太阳能电池、柔性电子产品、量子计算、盐水过滤等新技术的发展。这项研究计划通过考虑新系统的可能性为材料发现提出了一个新的方向，我们称之为杂化假自旋狄拉克材料。这些系统可能具有与技术相关的新特性。随着这些系统，新发现的奇异类石墨烯材料的领域，如Weyl半金属，拓扑绝缘体，和其他，将从理论上研究许多性质。将特别强调可能与光电子学应用相关的光学响应。研究生和其他高素质人员将接受高水平的培训，为最终在工业和学术界的职业生涯做准备。这一研究计划有望为对技术和社会具有重要意义的新量子材料的快速发展做出贡献。

Quantum materials are essential to the technologies of our modern world. This research program addresses two major areas of quantum materials research. One is the potential for discovery and understanding of superconductors operating at near room temperature. Superconductors are currently used in MRI machines in hospitals and are being developed for power transmission cables and magnetically-levitated high speed trains, among other applications. The current generation of materials only operates at very low temperature near -270oC requiring expensive liquid helium which is also in limited supply. Vast improvements could occur with the discovery of near room temperature superconductors, which would need little or no cooling. We are investigating mechanisms in materials that can give rise to such possibilities. A second direction is the investigation of so-called Dirac-Weyl materials. The recent discovery of such materials (graphene, a single layer of carbon atoms, is a prominent example) has pushed the development of new technologies for solar cells, flexible electronics, quantum computing, salt water filtration and more. This research program proposes a new direction for materials discovery by considering the possibility of new systems which we call hybrid pseudospin Dirac materials. These systems could have novel properties relevant to technology. Along with these systems, the realm of newly discovered exotic graphene-like materials such as Weyl semimetals, topological insulators, and others, will be investigated theoretically for many properties. Particular emphasis will be on optical response which may be relevant to optoelectronics applications. Graduate students and other highly qualified personnel will receive high-level training for eventual careers in industry and academia. This research program is expected to contribute to the rapid development of new quantum materials important to technology and society.