Coulomb-blockade peak-spacing distribution: Interplay of temperature and spin
نویسندگان
چکیده
We calculate the Coulomb-blockade peak-spacing distribution at finite temperature using the recently introduced ‘‘universal Hamiltonian’’ to describe the e-e interactions. We show that the temperature effect is important even at kBT;0.1D (D is the single-particle mean level spacing!. This sensitivity arises because: 1! exchange reduces the minimum energy of excitation from the ground state, and 2! the entropic contribution depends on the change of the spin of the quantum dot. Including the leading corrections to the universal Hamiltonian yields results in quantitative agreement with the experiments. Surprisingly, temperature appears to be the most important effect.
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Statistics of Coulomb Blockade Peak Spacings
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Distributions of Coulomb blockade peak spacing are reported for large ensembles of both unbroken (magnetic field B = 0) and broken (B ≠ 0) time reversal symmetry in GaAs quantum dots. Both distributions are symmetric and roughly gaussian with a width ~ 2–6% of the average spacing, with broad, non-gaussian tails. The distribution is systematically wider at B = 0 by a factor of ~ 1.2 ± 0.1. No ev...
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