Maximum-Density Droplet and Charge Redistributions in Quantum Dots at High Magnetic Fields

We have measured electron transport through a vertical quantum dot containing a tunable number (between 0 and 40) of electrons. Over a region of the magnetic field the electrons are spin polarized and occupy successive angular momentum states. This is the maximum-density-droplet (MDD) state. The stability region where the MDD is the ground state decreases for increasing electron number. The instability of the MDD and other transitions in this high $B$ region are accompanied by a redistribution of charge which abruptly changes the area of the electron droplet.