QUANTUM LIQUID OF VORTICES IN SUPERCONDUCTORS AT T=0

We investigate the existence of a T=0 quantum melting transition in the vortex system of a type-II superconductor. We find that homogeneous high-resistance thin films are good candidates for the observation of this effect. We calculate both the continuous dislocation-mediated melting line Bmd(T) as well as the first-order melting line BmG(T) driven by Gaussian fluctuations and present the resulting H-T phase diagram. At low temperatures the melting line BmG extrapolates to a value below the upper critical field, resulting in a quantum liquid state in the region BmG<B<Hc2. © 1994 The American Physical Society.