8 research outputs found
Duality Breaking of Vortex Configuration in a Hierarchical Honeycomb Network
We report measurements of Little-Parks oscillation on the hierarchical
honeycomb-superconducting network for investigating possible effects of
hierarchical structure in terms of spatial symmetry, parity and duality. We
observed an asymmetric Little-Parks oscillation about ,
although spatial symmetry was kept in the network. In comparison with a regular
honeycomb network, the asymmetric oscillation is attributed to hierarchy which
induces mixture of commensurate and incommensurate regions. The asymmetric
oscillation is found to indicate breaking of the duality of vortex
configuration.Comment: 12 pages, 6 figure
Parity Violation in a Single Domain of Spin-Triplet Sr2RuO4 Superconductors
We observed an unconventional parity-violating vortex in single domain
Sr2RuO4 single crystals using a transport measurement. The current-voltage
characteristics of submicron Sr2RuO4 shows that the induced voltage has
anomalous components which are even function of the bias current. The results
may suggest that the vortex itself has a helical internal structure
characterized by a Hopf invariant (a topological invariant). We also discuss
that the hydrodynamics of such a helical vortex causes the parity violation to
retain the topological invariant.Comment: Accepted for publication in Solid State Communication
Coexistence of the Kondo effect and spin glass physics in Fe-doped NbS2
We report the coexistence of the Kondo effect and spin glass behavior in Fe-doped NbS2 single crystals. The FexNbS2 shows the resistance minimum and negative magnetoresistance due to the Kondo effect, and exhibits no superconducting behavior at low temperatures. The resistance curve follows a numerical renormalization-group theory using the Kondo temperature K for x = 0.01 as evidence of Kondo effect. Scanning tunneling microscope/spectroscopy (STM/STS) revealed the presence of Fe atoms near sulfur atoms and asymmetric spectra. The magnetic susceptibility exhibits a feature of spin glass. The static critical exponents determined by the universal scaling of the nonlinear part of the susceptibility suggest a three-dimensional Heisenberg spin glass. The doped-Fe atoms in the intra- and inter-layers revealed by the x-ray result can realize the coexistence of the Kondo effect and spin glass