Intermediate low spin states in a few-electron quantum dot in the ν ≤ 1 regime

We study the effects of electron-electron interactions in a circular few-electron vertical quantum dot in such a strong magnetic field that the filling factor nu <= 1. We measure excitation spectra and find ground state transitions beyond the maximum density droplet (nu=1) region. We compare the observed spectra with those calculated by exact diagonalization to identify the ground state quantum numbers, and find that intermediate low-spin states occur between adjacent spin-polarized magic number states.