Exchange, correlation and compressibility in quantum wires: Anisotropic confinement model

We calculate the exchange energy, the correlation energy and the compressibility for a quantum wire using a three-sum-rule approach for the local-field correction. An anisotropic confinement model with delta-confinement in one direction and an oscillator confinement in the other direction is used in the calculation. We perform a systematic study versus the electron density and the width parameter of the wire and we present analytical and numerical results. In the low density regime the inverse compressibility is strongly negative and this might be observable via capacitance measurements. We predict a spin instability at low density, depending on the confinement parameter. Copyright (C) 1996 Elsevier Science Ltd