Quantum phase transitions in Coulomb-coupled trilayers

The ground-state electronic configurations of a system of three bidimensional electron gases, coupled by the exchange interaction, has been determined in the limit of zero tunneling among layers. Depending on the total density and the distance among layers, six different ground states are possible, with the one at the lowest density presenting spontaneous interlayer coherence. All transitions between different ground states proceed through abrupt charge transfer between layers.