A Model of Competing Orders and Its Application to a Novel Junction

Abstract

We introduce a simple Ginzburg-Landau model to describe coupled orders, such as antiferromagnetism and superconductivity in high-Tc cuprate superconductors, using which we can study the spatial modulation of the doping rate. We study junctions between non-doped and highly doped materials of cuprates. Possibility of a novel superconducting boundary state is suggested, which appears at temperatures higher than the maximum transition temperature of the bulk material at optimal doping. Experimental possibilities to realize this state is also discussed.