Quantum (Nano-scale) Limit for High-Tc Superconductors in a Parallel Magnetic Field

A method to describe layered superconductors under nano-scale (quantum limit (QL)) conditions, where the "sizes" of quasi-classical electron orbits in a parallel magnetic field are less or of the order of the distances between conducting layers, is suggested. We argue that these unique QL superconducting properties have to be observed in a broad class of layered high-Tc and organic superconductors in experimental magnetic fields, H > 5 - 50T.