Abstract
Low temperature measurements of the magnetic susceptibility of LaCuO4 doped with Sr (LSCO) suggest that superconducting transition is associated with the disappearance of the vortex liquid. This note draws attention to the possibility that these vortices can be identified with the soliton-like charge carriers introduced in a previous theory of spin–orbit localization in layered poor conductors. In two-dimensions, these solitons are vortex-like, while in three-dimensional systems they are monopole-like. In either case, there is a natural mechanism for the pairing of spin-up and spin-down solitons. At low temperatures, there is a also cross-over transition which is a function of carrier density between a state where the solitons can move independently and a condensate state where the spin-up and spin-down solitons in neighbouring layers are paired.
Acknowledgements
The author thanks B. Alder, A. Bernevig, M. Fluss, R. Laughlin, S. McCall, G. Lonzarich, C. Panagopoulos, P. Riseborough, D. Santiago, J. Smith and S.-C. Zhang for helpful discussions. This work was performed under the auspices of the US Department of Energy at the Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344.