We study the conductance of a quantum T-junction coupled to two electron reservoirs and a quantum dot. In the absence of electron-electron interactions, the conductance g is sensitive to interference between trajectories which enter the dot and those which bypass it. We show that including an intra-dot charging interaction has a marked influence-- it can enforce a coherent response from the dot at temperatures much larger than the single particle level spacing Δ. The result is large oscillations of g as a function of the voltage applied to a gate capacitively coupled to the dot. Without interactions, the conductance has only a weak interference signature when T>Δ.
@article{arxiv.cond-mat/0105281,
title = {Interaction Induced Restoration of Phase Coherence},
author = {A. A. Clerk and P. W. Brouwer and V. Ambegaokar},
journal= {arXiv preprint arXiv:cond-mat/0105281},
year = {2009}
}
Comments
4 pages, 2 figures. Typos corrected, minor changes for clarity. Accepted for publication in Phys. Rev. Lett