We study the fermionic states of the antiferromagnetically ordered vortex cores predicted to exist in the superconducting phase of the proposed SO(5) model of strongly correlated electrons. Our model calculation gives a natural explanation of the recent STM measurements on BSCCO, which in surprising contrast to YBCO revealed completely insulating vortex cores.

• Received 24 September 1999

DOI:https://doi.org/10.1103/PhysRevB.61.6298