Superconducting Correlation in Orbital Magnetism of Quantum Dots

We study orbital magnetism in disk quantum dots with superconductor/normal metal junctions. We calculate the energy levels and then the magnetization by solving the Bogoliubov-deGennes equation numerically. As a result, we find that characteristic energy levels appear below the superconducting gap and make a significant paramagnetic contribution to the magnetization. The wave functions of the subgap levels show a novel field dependence which is interpreted in terms of the quasi-classical picture.