Europhys. Lett.
Volume 76, Number 1, October 2006
Page(s) 95 - 101
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 23 August 2006
Europhys. Lett., 76 (1), pp. 95-101 (2006)
DOI: 10.1209/epl/i2006-10219-1

Gate voltage effects in capacitively coupled quantum dots

A. K. Mitchell, M. R. Galpin and D. E. Logan

Oxford University, Physical and Theoretical Chemistry Laboratory South Parks Road, Oxford OX1 3QZ, UK

received 1 July 2006; accepted in final form 1 August 2006
published online 23 August 2006

We study a system of two symmetrical capacitively coupled quantum dots, each coupled to its own metallic lead, focusing on its evolution as a function of the gate voltage applied to each dot. Using the numerical renormalization group and poor man's scaling techniques, the low-energy Kondo scale of the model is shown to vary significantly with the gate voltage, being exponentially small when spin and pseudospin degrees of freedom dominate; but increasing to much larger values when the gate voltage is tuned close to the edges of the Coulomb blockade staircase where low-energy charge-fluctuations also enter, leading thereby to correlated electron physics on energy/temperature scales more accessible to experiment. This range of behaviour is also shown to be manifest strongly in single-particle dynamics and electron transport through each dot.

71.27.+a - Strongly correlated electron systems; heavy fermions.
72.15.Qm - Scattering mechanisms and Kondo effect.
73.63.Kv - Quantum dots.

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