具有时间反演对称破缺性的方钴矿超导体的能隙结构

Unconventional superconductivity has attracted much attention in the field of condensed matter physics, since the study of pairing origin of unconventional superconductors is significant to increasing the superconducting transiton temperature. We propose to study the recently discovered time reversal symmetry breaking unconventional superconductor PrPt4Ge12, and its rare earth doping compounds by performing muon spin relaxation/rotation, measuring specific heat and electrical resistivity at low temperatures, to identify the symmetry of its superconducting energy gap and time reversal symmetry. We hope to prvoe that, with some rare earth doping concentration, this compound has the symmetry to be analogous to A phase of He3 which is known to have a time reversal symmetry breaking p-wave symmetry. In addition, same study will be applied to another recently discovered time reversal symmetry breaking superconductor LaNiC2. The proposed work will not only help to comprehend the complex unconventional superconducting pairing and shed light on a consistent theoretical description of all aspect of unconventional superconductivity, but also offer potential opportunities in quantum computing since it includes the finding of higher temperture superconductor with properties similar to A phase of He3 which is significant to quantum computing.

非传统超导电性是凝聚态物理研究的热点之一。研究非常规超导体的超导微观机制对提高超导相变温度具有重要指导意义。本课题拟结合Muon Spin Relaxation/Rotation 实验技术和低温输运、热学测量，研究最近发现的具有时间反演对称破缺超导性质的新型非常规超导体PrPt4Ge12及其稀土元素掺杂化合物。从超导能隙分布、能隙函数对称性、时间反演对称破缺等方面揭示其超导性质，证明在一定掺杂范围内的化合物具有类比于液氦超流A态的超导性质，是具有时间反演对称破缺的p波超导有序参数的超导体，并和最近发现的时间反演对称破缺超导体LaNiC2进行比较。本项目研究将为揭示这类非传统超导体的微观超导机制提供重要线索。同时，由于液氦超流A态对于高能量子计算具有重要意义，本项目研究的超导体类比于液氦超流A态，且相变温度远高于液氦超流A态，将给高能量子计算提供重要的潜在研究途径。

本课题结合Muon Spin Relaxation/Rotation （MuSR）实验技术和低温输运、热学测量，研究最近发现的具有时间反演对称破缺超导性质的新型非常规超导体PrPt4Ge12及其稀土元素掺杂化合物。我们成功制备了高质量方钴矿样品PrPt4Ge12及其稀土元素Ce的掺杂样品：Pr1-xCexPt4Ge12 (x = 0.05, 0.06, 0.07, 0.1, 0.25)。进行了在不同磁场环境下的电阻率、比热、磁化率测量、以及零场下的MuSR研究。从超导能隙分布、能隙函数对称性、时间反演对称破缺等方面揭示其非传统性超导性质，发现了稀土元素Ce5%以上的掺杂范围内的化合物具有两个对磁场反应完全不同的超导相，其中至少一个超导相具有时间反演对称破缺性质。我们的结果表明这类化合物存在具有类比于液氦超流A态的超导性质，是具有时间反演对称破缺的p波超导有序参数的超导体。发表相关论文4篇，包括1篇Physical Review Letters，3篇Physical Review B。培养博士后1名，博士研究生3名。..