Abstract: 

The superconductor–insulator (SI) transition in two-dimensional Ta thin films is investigated by controlling both film thickness and magnetic field. An intriguing metallic phase appears between a superconducting and an insulating phase within a range of film thickness and magnetic field. In order to understand the nature of the SI transition in the thickness-tuned metallic and superconducting samples, we performed various measurements including temperature and electric field scaling analyses, transport mechanism near the critical current, magnetoresistance near the onset of vortex flow. With the various measurements, we conclude that Tantalum superconducting thin films can be categorized into weakly disordered films exhibiting superconductor-metal-insulator transition due to the vortex dynamics that interferes the superconducting phase coherence.