NONDISSIPATIVE LOGIC DEVICE NOT BASED ON 2 COUPLED QUANTUM DOTS

Non-dissipative dynamics of interacting electrons in a pair of tunnel- coupled quantum dots is studied theoretically within the framework of the Hubbard model. Various values of intra-dot Coulomb repulsion energ y U and inter-dot tunneling energy V are considered, which correspond to various size of the dots and various distance between them. In the ground state, the average value of the spin projection (magnetic momen t) at each dot is zero. The input signal (local external magnetic fiel d H) applied to one of the dots at a time t = 0 causes the electronic subsystem to evolve in such a way that magnetic moments of quantum dot s become oriented in the opposite directions at any time t > 0. For an y set of U and V, there exist optimal values of H and t which maximize the absolute values of magnetic moments at both dots, and magnetic mo ments become almost saturated. Thus, the antiferromagnetic-like spin o rdering can be realized at the stage of coherent temporal evolution, w ell before the relaxation to a new ground state due to the inelastic p rocesses. This effect (''dynamical antiferromagnetism'') may be used f or implementation of a logic function NOT in an extremely short time. A possibility to use the arrays of quantum dots as high-speed single-e lectron devices of new generation is discussed.