U.S.-Federal Republic of Germany Cooperative Research on Heavy Fermion Systems

目标和与计划目标的相关性：本推荐奖 将支持一个为期三年的合作研究项目， Gregory R.佛罗里达大学的斯图尔特和弗兰克教授 Steglich，Technische Hochschule，达姆施塔特，联邦共和国德国。 他们将试图描述新的重费米子系统和那些 通过使用电阻率，磁化率， 在25 T的磁场中的比热、热膨胀和热功率 温度降至0.050K。 这一建议涉及一个高度 目前的兴趣在固体物理学，超导在高度- 相关电子金属，有效电子质量为 Steglich教授发现，高质量电子（重电子） 费米子）是某些材料的超导成分。 的 为什么有些系统在低于1 K时变得超导，而另一些系统在低于1 K时变得超导， 变得有磁性或根本不有序仍然无法解释。 的 拟议的合作研究将解决这一问题，以及其他 关于重费米子基态的原因和 是否会在重费米子系统中观察到超导性， 到标准超导电子配对。 这项研究将 从两位研究人员的合作经验中获益 以及他们两个实验室的设备。 项目 从而有助于实现NSF合作科学的一个重要目标 与西欧合作的项目， 把来自美国和欧洲的科学家聚集在一起， 有着相似的研究兴趣，并希望从事互利合作的人 研究合作。 该奖项的资金将支持必要的 美国委托人的交通费和部分生活费 调查员预计Steglich教授将回访。 建议的优点：合作的美国和外国调查人员是 他们以前的研究成果受到尊重，而且有一个 非常好的前景，这项拟议的研究将导致一个 对科学知识的重大贡献。 拟议 合作为美国调查人员提供了工作机会， 与国外领先的研究小组合作， 国外的设施是对他自己的补充。 工作计划是 合理，预算合理。 目前，该领域的研究 在美国和国外都在大力推行。 德意志 Forschungsgemeinschaft（DFG）正在为以下方面提供德国对应支持： 已批准将这一活动列入项目， NSF和DFG之间的谅解备忘录。 资助：该奖项不会重复其他资助。 德国 学术交流服务（DAAD）将支持旅行和一个月的 斯图尔特教授在这个奖项的第一年的每日津贴。

Objectives and Relevance to Program Objectives: This recommended award would support a three-year cooperative research project between Professor Gregory R. Stewart, University of Florida, and Professor Frank Steglich, Technische Hochschule, Darmstadt, Federal Republic of Germany. They will try to characterize new heavy fermion systems and those that are already known by using resistivity, magnetic susceptibility, specific heat in fields to 25T, thermal expansion, and thermopower at temperatures down to 0.050K. This proposal deals with a topic of high current interest in solid state physics, superconductivity in highly- correlated-electron metals with an effective electron mass of 200 me. Professor Steglich has found that high-mass electrons (heavy fermions) are the superconducting components of certain materials. The reason why some systems become superconducting below 1K, while others become magnetic or do not order at all remains unexplained. The proposed cooperative research will address this issue, as well as other questions concerning the cause of the heavy fermion ground state and whether superconductivity will be observed in heavy fermion systems due to standard superconductivity electron pairing. The research will benefit from the experience of the two researchers in working together and from the equipment available in their two laboratories. The project thus contributes to an important objective of NSF's cooperative science programs with Western Europe, which is to stimulate scientific progress by bringing together scientists from the U.S. and Europe who have similar research interests and who wish to engage in mutually beneficial research cooperation. Funds from this award would support necessary transportation and partial subsistence expenses for the U.S. principal investigator. Return visits by Professor Steglich are anticipated. Merit of Proposal: The cooperating U.S. and foreign investigators are respected for their previous research accomplishments, and there is a very good prospect that this proposed research will lead to a significant contribution to scientific knowledge. The proposed cooperation presents the U.S. investigator with the opportunity to work with a leading foreign research group and to use highly specialized facilities abroad that are complementary to his own. The work plan is sound and the budget is reasonable. Research in this field is currently being vigorously pursued in the U.S. and abroad. The Deutsche Forschungsgemeinschaft (DFG) is providing German counterpart support for the project and has approved the inclusion of this activity under the Memorandum of Understanding between the NSF and the DFG. Funding: This award will not duplicate other funding. The German Academic Exchange Service (DAAD) will support the travel and one-month of per diem for Professor Stewart during the first year of this award.