Determination of the Exact Symmetry of the Pairing State in Sr2RuO4

关于Sr2RuO4中的非常规(例如，奇宇称(自旋三重态或p波))配对态的实验证据一直在增加。这种系统是已知的唯一不含铜的层状钙钛矿超导体(T_c=1.3-1.5K)。这个GOALI计划汇集了来自宾夕法尼亚州立大学、IBM、喷气推进实验室和京都大学的研究人员，进行最终的实验工作，以解决关于这种令人兴奋的新材料的一些关键问题。主要目的是通过扫描SQUID探头对单晶基结构的相敏实验来确定Sr2RuO4中配对态的宇称(偶或奇)。我们将研究In/Sr2RuO4(或Pb/Sr2RuO4)结，以加深我们对常规S波与非常规超导体之间约瑟夫森耦合的理解。Au/Sr2RuO4(或Ag/Sr2RuO4)金属接触将被用来寻找与Andreev过程相关的新的表面束缚态。对超导单晶Sr2RuO4的隧道测量将继续确定Sr2RuO4的能隙，这些测量旨在了解这种材料的超导机制。在开展这项工作时，宾夕法尼亚州立大学、IBM和喷气推进实验室的科学家将能够在合作环境中交流思想，并在所有阶段积极参与研究生的培训。反过来，学生将有机会获得在非常不同的环境中工作的第一手经验，包括学术、工业和NASA研究实验室。这种环境将为他们规划未来的职业生涯提供更广阔的视角。%最近，唯一已知的不含铜的层状钙钛矿型超导体(T_c=1.3-1.5K)Sr2RuO_4在超导研究界引起了极大的关注。特别是，在Sr2RuO4中发现了一种非传统的、可能是奇宇称(自旋三重态或p波)对状态的实验证据，这引起了对这种新超导材料的极大兴奋。该程序的目的是通过相敏和隧穿实验确定Sr2RuO4中超导对称态的精确对称性，并研究非常规和常规S波超导体之间的约瑟夫森耦合。在开展这些研究活动时，宾夕法尼亚州立大学、IBM和喷气推进实验室将建立一个富有成效的长期合作伙伴关系，为我们的下一代科学家和工程师培养学生。反过来，学生将有机会获得在非常不同的环境中工作的第一手经验，包括学术、工业和NASA研究实验室。这样的环境将为他们在规划未来职业生涯时提供更广阔的视角。该GOALI项目由材料研究部(凝聚态物理计划)和数学和物理科学局多学科活动办公室(MPS/OMA)联合支持。

9974327LiuExperimental evidence for an unconventional (e.g. an odd parity (spin-triplet or p-wave)) pairing state in Sr2RuO4 has been growing. Such a system is the only known layered perovskite superconductor (Tc = 1.3 - 1.5K) that does not contain copper. This GOALI program brings together researchers from Penn State, IBM, JPL, and Kyoto University to carry out definitive experimental work that will address some key issues on this exciting new material. The main thrust is to determine the parity (even or odd) of the pairing state in Sr2RuO4 through phase-sensitive experiments on single-crystal-based structures using a scanning SQUID probe. In/Sr2RuO4 (or Pb/Sr2RuO4) junctions will be studied to further our understanding of Josephson coupling between a conventional s-wave and an unconventional superconductor. Au/Sr2RuO4 (or Ag/Sr2RuO4) metallic contacts will be used to search for novel surface-bound states associated with the Andreev process. Tunneling measurements on superconducting single crystals of Sr2RuO4 which are aimed at the understanding of the mechanism of superconductivity in this material will be continued to determine the energy gap of Sr2RuO4. In carrying out this work, scientists at Penn State, IBM, and JPL will be able to exchange ideas in a collaborative environment and be actively involved in the training of graduate students at all stages. Students in turn will have the opportunity to gain first hand experience working in very different settings including academic, industrial, and NASA research laboratories. This environment will provide them with a broader perspective when planning their future careers.%%%Recently Sr2RuO4, the only known layered perovskite superconductor (Tc = 1.3 - 1.5K) that does not contain copper, has attracted much attention in the superconductivity research community. In particular, experimental evidence for an unconventional, likely odd-parity (spin-triplet or p-wave) pairing state found in Sr2RuO4 has generated much excitement on this new superconducting material. The goals of this GOALI program are to determine the exact symmetry of the superconducting pairing state in Sr2RuO4 through phase sensitive and tunneling experiments and to study the Josephson coupling between an unconventional and a conventional s-wave superconductor. In carrying out these research activities, a productive, long-term partnership between Penn State, IBM, and JPL will be established to train students for our future generation of scientists and engineers. Students in turn will have the opportunity to gain first hand experience working in very different settings including academic, industrial, and NASA research laboratories. Such an environment will provide them with a broader perspective when planning their future careers. This GOALI project is supported jointly by the Division of Materials Research (Condensed Matter Physics Program) and the Directorate for Mathematical and Physical Sciences Office of Multidisciplinary Activities (MPS/OMA).***