Europhys. Lett.
Volume 71, Number 6, September 2005
Page(s) 973 - 979
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 24 August 2005
Europhys. Lett., 71 (6), pp. 973-979 (2005)
DOI: 10.1209/epl/i2005-10184-1

Mesoscopic Kondo problem

R. K. Kaul, D. Ullmo, S. Chandrasekharan and H. U. Baranger

Department of Physics, Duke University - Durham, NC 27708-0305, USA

received 29 April 2005; accepted in final form 21 July 2005
published online 24 August 2005

We study the effect of mesoscopic fluctuations on a magnetic impurity coupled to a spatially confined electron gas with a temperature in the mesoscopic range (i.e. between the mean level spacing $\Delta$ and the Thouless energy $E_{\ab{Th}}$). Comparing "poor-man's scaling" with exact Quantum Monte Carlo, we find that for temperatures larger than the Kondo temperature, many aspects of the fluctuations can be captured by the perturbative technique. Using this technique in conjunction with semi-classical approximations, we are able to calculate the mesoscopic fluctuations for a wide variety of systems. For temperatures smaller than the Kondo temperature, we find large fluctuations and deviations from the universal behavior.

73.23.Hk - Coulomb blockade; single-electron tunneling.
72.15.Qm - Scattering mechanisms and Kondo effect.
73.63.Kv - Quantum dots.

© EDP Sciences 2005