The interaction between square d-dot’s

A d-dot is a nano-scaled superconducting composite structure, which is a d-wave superconducting dot embedded in an s-wave superconductor, and behaves as a 1/2 spin because it has spontaneous half-integer quantum fluxes around its corners. Solving the two-components Ginzburg–Landau equations for two equal square d-dot’s with various distances and directions between them, we investigated the interaction between two equal square d-dot’s. The results show the ferromagnetic configuration is more stable than the antiferromagnetic one at large distance and for all directions. But at small distance the antiferromagnetic configuration becomes more stable instead of the ferromagnetic configuration, when the dot size is small.