EFFECT OF FINITE QUANTUM-WELL WIDTH ON THE COMPRESSIBILITY OF A 2-DIMENSIONAL ELECTRON-GAS

Double quantum-well structures have been used to measure the inverse c ompressibility (kappa(-1)) of a two-dimensional electron gas as a func tion of the confining quantum-well width. The lower layer is contacted independently and carrier density changes within this layer are used to measure kappa(-1) of the upper layer. As the well width increases w e observe a decrease in kappa(-1) which may be attributed to the effec t of the Hartree term. The inclusion of Hartree effects produces the c orrect trend of kappa(-1) with well width, although discrepancies stil l exist between the model and experiment.