US-Federal Republic of Germany Cooperative Research on HeavyFermion Systems

该奖项支持佛罗里达大学的Gregory R.Stewart教授与德意志联邦共和国达姆施塔特工业大学核物理研究所的Frank Steglich教授合作研究重费米子系统的物理。合作的实验室为拟议中的费米子超导研究带来了大量互补的实验专业知识。斯蒂格利希教授的团队发现了第一个重费米子超导体。他们在比热、临界领域、热膨胀和热电势以及在极低温度(0.050开尔文)下工作方面拥有相当多的专业知识和集体知识。佛罗里达大学的团队在铀-铍-13(UBe.13)样品制备和小质量研究--强磁场中的比热--方面具有很强的实力。重费米子系统在低温下表现出异常大的比热，再加上它们接近磁性行为，使得这些铯和铀基化合物中出现超导电性是意想不到的。合作的研究小组将研究超导配对的性质，以及正常态性质和超导电性之间的关系。他们将在理解宇宙空间中正常态高有效质量来源的最新突破的基础上再接再厉，以探索超导电性的可能含义。基于重费米子电子系统的不同寻常的性质以及它们在某些方面与高温超导体的相似性，在理解重费米子电子系统方面的进展可能会在磁性和超导方面有长期的应用。

This award supports Professor Gregory R. Stewart of the University of Florida to collaborate in research on the physics of heavy fermion systems with Professor Frank Steglich of the Institute for Nuclear Physics of the Technical University of Darmstadt, Federal Republic of Germany. The collaborating laboratories bring substantially complementary experimental expertise to the proposed study of >superconductivity in fermions. Professor Steglich's group discovered the first heavy fermion >superconductor. They have considerable expertise and collective knowledge in specific heat, critical fields, thermal expansion, and thermopower and in working with very low temperatures (0.050 Kelvin.) The University of Florida group offers substantial strengths in Uranium.Beryllium13 (UBe.13) sample preparation and studies of small mass.specific heat in high magnetic fields. Heavy fermion systems display anomalously large specific heats at low temperatures which, when coupled with their nearness to magnetic behavior, makes the occurrence of superconductivity in these Cesium and Uranium based compounds unexpected. The collaborating research groups will study the nature of the superconducting pairing and the relationship between normal state properties and superconductivity. They will build on their recent breakthrough in understanding the source of the normal state high effective mass in UBe.13, in order to explore possible implications for superconductivity. Advances in understanding heavy fermion electron systems may have long term applications in magnetism and superconductivity based on their unusual properties and their similarities in some respects to high temperature superconductors.