Exchange and correlation effects on drag in low density electron   bilayers: Coulomb and virtual-optical-phonon-mediated electron-electron   interaction
  We investigate the effect of exchange and correlation (xc) in low-density electron bilayers. Along with the direct Coulomb interaction, the effective electron-electron interaction mediated by the exchange of virtual polar optical (PO) phonons is considered. We find that the introduction of xc corrections results in a significant enhancement of the transresistivity and qualitative changes in its temperature dependence. The virtual PO-phonon contribution behaves similarly to the Coulomb drag and reduces noticeably the total drag thereby resulting in a better agreement with the recent experimental findings. 
S. M. Badalyan, C. S. Kim, and G. Vignale