Exchange-driven bilayer-to-monolayer charge transfer in an asymmetric double-quantum-well

We present data which shows for the first time that an exchange-driven bilayer-to-monolayer transition occurs in an externally biased double quantum well system at B=0 as the total carrier density is increased. This transition is due to the negative compressibility of the low density carrier systems and the layer imbalance caused by external gate biases.