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Impurity effects in few-electron quantum dots: Incipient Wigner molecule regime

B. Reusch·R. Egger
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Abstract

Numerically exact path-integral Monte Carlo data are presented for $N\leq 10$ strongly interacting electrons confined in a 2D parabolic quantum dot, including a defect to break rotational symmetry. Low densities are studied, where an incipient Wigner molecule forms. A single impurity is found to cause drastic effects: (1) The standard shell-filling sequence with magic numbers $N=4,6,9$, corresponding to peaks in the addition energy $Δ(N)$, is destroyed, with a new peak at N=8, (2) spin gaps decrease, (3) for N=8, sub-Hund's rule spin S=0 is induced, and (4) spatial ordering of the electrons becomes rather sensitive to spin. We also comment on the recently observed bunching phenomenon.

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B. Reusch, R. Egger. 2003-07-17. Impurity effects in few-electron quantum dots: Incipient Wigner molecule regime. https://doi.org/10.1209/epl%2Fi2003-00137-2

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