Many-body effects on the symmetric-antisymmetric gap in double quantum wells in strong magnetic fields

Abstract

We study the effect of the electron-electron interaction on the symmetric-antisymmetric energy gap in double quantum well systems in strong magnetic field at total filling factor \ensuremath{\nu}=1. We sum self-energy diagrams up to second order, and also we evaluate the self-energy in the GW\ensuremath{\Gamma} approximation. We find that in the GW\ensuremath{\Gamma} approximation the symmetric-antisymmetric energy gap collapses when the charge-density excitation develops a soft mode. Then the charge-density wave instability, which occurs in the double quantum well system at \ensuremath{\nu}=1, is accompanied by a transition to a metallic system.