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Extracting the ground-state spin of a quantum dot from the conductance peaks in a parallel magnetic field at finite temperature

Daniel Huertas-Hernando·Y. Alhassid
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Abstract

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.

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Daniel Huertas-Hernando, Y. Alhassid. 2004-04-27. Extracting the ground-state spin of a quantum dot from the conductance peaks in a parallel magnetic field at finite temperature. https://arxiv.org/abs/cond-mat/0404619

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