Type I superconductors have no electric field nor magnetic field inside of them, when they are in the superconducting state. This means no voltage difference across any two points or regions inside of them. Yet they carry a current. This means the Cooper pairs (or the electrons responsible for the current) are moving in a particular direction.
My question is, what determine this particular direction, if there's no voltage involved?
Edit: If we have to apply a voltage initially, to get the Cooper pairs moving in a particular direction and then we remove that voltage and the current will still persist, then it would mean that the superconductor has a sort of "memory" in that it's possible to retrieve where (and how strong?) the voltage was applied? Does it also mean that the superconductor behaves the same way with and without the applied voltage? If so, that would be very strange and I'd like some clarifications.