Determining the superconducting order parameter of UPt3 with Josephson junction interferometry

UPt3;Josephson junctions;unconventional superconductivity;Josephson interferometry;superconducting order parameter

Strand, Joel D.

关键词: UPt3;    Josephson junctions;    unconventional superconductivity;    Josephson interferometry;    superconducting order parameter;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/15582/Strand_Joel.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

We report evidence for a complex low-temperature superconducting phase in UPt3 that breaks time-reversal symmetry and exhibits a phase shift of Pi in the superconducting order parameter between the a- and b-axes. We also report evidence for nodes in the amplitude of the superconducting energy gap in the high-temperature phase of UPt3. These nodes occur 45 degrees between the a- and b-axes and fill in as an out-of-phase energy gap component develops. This evidence supports the E2u representation of the superconducting order parameter. These measurements were taken by fabricating Pb-Cu-UPt3 Josephson junctions on polished and as-grown surfaces of UPt3 single crystals. By measuring the critical current through the junctions and varying the applied magnetic field, temperature, and angle of the junctions, we obtained information on the phase and magnitude of the superconducting order parameter.