Observation of the parallel-magnetic-field-induced superconductor-insulator transition in thin amorphous InO films

We study the response of a thin superconducting amorphous InO film with variable oxygen content to a magnetic field. A field-induced superconductor-insulator transition (SIT) is observed that is very similar to the one in normal magnetic fields. As the boson-vortex duality, which is the keystone of the theory of the field-induced SIT, is obviously absent in the parallel configuration, we have to draw a conclusion about the theory’s insufficiency.