The tetracritical point seen in the HT phase diagram of UPt3 for several orientations of H strongly constrains Ginzburg-Landau (GL) theories, as the GL "Hamiltonian" must have a conserved quantity Q. A two-component vector order parameter model has a Q for H∥c but no tetracritical point. Among accidentally nearly degenerate like-parity order parameters, only the case where one behaves as an A and the other as a B representation of D6h (the point group of UPt3) is allowed. This model is studied and compared to experiment.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering