Theory of Neutron Diffraction from the Vortex Lattice in UPt3

TL;DR

This paper develops a theoretical model for neutron diffraction observations in UPt3's vortex lattice, explaining anomalous field-dependent behaviors and phase transition effects that challenge conventional superconductivity theories.

Contribution

It introduces a two-component superconductivity theory to interpret unusual vortex lattice structures and phase transition phenomena in UPt3.

Findings

Anomalous field dependence of vortex lattice aspect ratio in UPt3

Change in effective coherence length at phase transition

Partial discrepancy between theory and experimental data

Abstract

Neutron scattering experiments have recently been performed in the superconducting state of UPt3 to determine the structure of the vortex lattice. The data show anomalous field dependence of the aspect ratio of the unit cell in the B phase. There is apparently also a change in the effective coherence length on the transition from the B to the C phases. Such observations are not consistent with conventional superconductvity. A theory of these results is constructed based on a picture of two-component superconductivity for UPt3. In this way, these unusual observations can be understood. There is a possible discrepancy between theory and experiment in the detailed field dependence of the aspect ratio.