Coulomb-blockade peak-spacing distribution: Interplay of temperature and spin

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 k(B)T similar to0.1 Delta (Delta 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.