Impurity-induced localization of Bose-Einstein condensates in one-dimensional optical lattices

The impurity-induced localization of two-component Bose-Einstein condensates loaded into deep one-dimensional optical lattices is studied both analytically and numerically. It is shown that, the analytical criteria for self-trapping and moving soliton/breather of the primary-component condensate are modified significantly by an admixture of an impurity component (the second component). The realization of the self-trapped state and the moving soliton/breather states of the primary-component becomes more easy with the minor admixture of the impurity-component, even if the two components are partly overlapped. (general)