Collapse of the Zeeman gap in quantum dots due to electronic correlations

We present results of calculations and "lateral" magnetotunneling experiments on small quantum dots in the few-electron regime. In the transition from a spin-unpolarized to a spin-polarized droplet, a systematic oscillation of the chemical potential of the droplet as a function of the magnetic field correlates with oscillations in the current amplitude. The temperature dependence of the current minima indicates that the minima are associated with the collapse of the Zeeman gap in the quantum Hall droplet. The collapse of the Zeeman gap is associated with the nontrivial magnetic field dependence of the spin polarization of a quantum Hall droplet due to electronic correlations. [S0163-1829(99)05304-7].