Electron spectra in low-dimensional crystalline systems

Considering the models of spatially bounded structures and with broken translational symmetry (ultrathin films, quantum wires and dots), we have found the electron spectra using the method of two-time anticommutator Green´s functions. The electron spectra are distinctly discrete and possess gaps (which we the consequence of the spatial boundedness of the system). Using the definition of the activation temperature of the electron subsystem we connected these results with better superconductive properties of micro samples, which can be a possible explanation of high critical temperature of HTC ceramics.