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Arrays of quantum dots have attracted significant
interest due to the unprecedented experimental control in assembling such arrays, and the resulting ability to custom-design their
electronic structure and transport properties.
The continued miniaturization of such arrays raises the important question of how
the non-equilibrium transport properties in nanoscopic arrays differ from those in mesoscopic ones and how they evolve across different
length scales.
In this talk, I describe how the interplay between dissipation, disorder, quantum confinement and Coulomb interaction gives rise to a series of novel non-equilibrium quantum effects in QD arrays. In particular, the dots' dissipative nature leads to a spatial variation of the chemical potential, reflecting the array's resistance, which changes qualitatively with increasing disorder, and breaks the invariance of the current under bias reversal. Moreover, the array's nanoscopic size yields an algebraic low-temperature dependence of the current in disordered arrays, in contrast to the exponential scaling observed in mesoscopic arrays. A local Coulomb interaction results in a splitting of a dot's energy level, giving rise to a Coulomb blockade in the charge transport, which is softened with increasing dissipation and/or size of the array. Finally, I show that the spatial flow of current varies with the applied bias and gate voltage, thus demonstrating the existence of current eigenmodes. In the presence of disorder, these eigenmodes are reduced to one-dimensional valleys of current. |
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