2004/04/27 by Daniel Huertas-Hernando, Huertas-Hernando, Daniel, Y. Alhassid +1
Physics and Astronomy · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.cond-mat/0404619
4 pages, 3 figures
arxiv created 2004/04/27 · arxiv updated 2009/12/01
We derive a closed expression for the finite-temperature conductance of a Coulomb-blockade quantum dot in the presence of an exchange interaction and a parallel magnetic field. Parallel-field dependence of Coulomb-blockade peak position has been used to determine experimentally the ground-state spin of quantum dots. We find that for a realistic value of the exchange interaction, the peak motion can be significantly affected at temperatures as low as kT ~ 0.1 Delta, with Delta being the mean level spacing in the dot. This temperature effect can lead to misidentification of the ground-state spin when a level crossing occurs at low fields. We propose an improved method to determine unambiguously the ground-state spin. This method takes into account level crossings and temperature effects at a finite exchange interaction.