Abstract
We study charge stability of a symmetric triple quantum dot by using the Hund-Milliken method. As the interdot tunnel coupling increases from zero, the stability deviates continuously from that of the capacitance model. We demonstrate how the stability diagram is modified by the tunneling coupling, especially, around the sextuple point. It is shown that the characteristic feature of the sextuple point, omnidirectional charge transport, is maintained even though the sixfold degeneracy is lifted by the tunnel coupling. This is possible because the ground state near the broken sextuple point shows election or hole delocalization over the three quantum dots.
- Received 16 April 2012
DOI:https://doi.org/10.1103/PhysRevB.87.045302
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