AUTHOR=Avers K. E. , Gannon W. J. , Leishman A. W. D. , DeBeer-Schmitt L. , Halperin W. P. , Eskildsen M. R. 

TITLE=Effects of the Order Parameter Anisotropy on the Vortex Lattice in UPt3

JOURNAL=Frontiers in Electronic Materials

VOLUME=2

YEAR=2022

URL=https://www.frontiersin.org/journals/electronic-materials/articles/10.3389/femat.2022.878308

DOI=10.3389/femat.2022.878308

ISSN=2673-9895

ABSTRACT=<p>We have used small-angle neutron scattering to determine the vortex lattice phase diagram in the topological superconductor UPt<sub>3</sub> for the applied magnetic field along the crystalline <italic>c</italic>-axis. A triangular vortex lattice is observed throughout the superconducting state, but with an orientation relative to the hexagonal basal plane that changes with field and temperature. At low temperature, in the chiral B phase, the vortex lattice undergoes a non-monotonic rotation with increasing magnetic field. The rotation amplitude decreases with increasing temperature and vanishes before reaching the A phase. Within the A phase an abrupt ±15° vortex lattice rotation was previously reported by Huxley <italic>et al.</italic>, Nature <bold>406</bold>, 160-164 (2000). The complex phase diagram may be understood from competing effects of the superconducting order parameter, the symmetry breaking field, and the Fermi surface anisotropy. The low-temperature rotated phase, centered around 0.8 T, reported by Avers <italic>et al.</italic>, Nature Physics <bold>16</bold>, 531-535 (2020), can be attributed directly to the symmetry breaking field.</p>