%0 Journal Article
%T Spontaneously broken time-reversal symmetry in high-temperature superconductors
%A Mikael H£¿kansson
%A Tomas L£¿fwander
%A Mikael Fogelstr£¿m
%J Physics
%D 2014
%I arXiv
%R 10.1038/nphys3383
%X Conventional superconductors are strong diamagnets that through the Meissner effect expel magnetic fields. It would therefore be surprising if a superconducting ground state would support spontaneous magnetics fields. Such time-reversal symmetry broken states have been proposed for the high-temperature superconductors, but their identification remains experimentally controversial. Here we show a route to a low-temperature superconducting state with broken time-reversal symmetry that may accommodate currently conflicting experiments. This state is characterised by an unusual vortex pattern in the form of a necklace of fractional vortices around the perimeter of the material, where neighbouring vortices have opposite current circulation. This vortex pattern is a result of a spectral rearrangement of current carrying states near the surfaces.
%U http://arxiv.org/abs/1411.0886v1