Spectral properties of a double-quantum-dot structure: A causal Green's function approach

Spectral properties of a double quantum dot (QD) structure are studied by a causal Green's function (GF) approach. The double QD system is modeled by an Anderson-type Hamiltonian in which both the intra- and interdot Coulomb interactions are taken into account. The GF's are derived by an equation-of -motion method and the real-space renormalization-group technique. The nume rical results show that the average occupation number of electrons in the Q D exhibits staircase features and the local density of states depends appre ciably on the electron occupation of the dot.