Physics of a metal-correlated barrier-metal heterostructure

We consider a heterostructure of a metal and a barrier with onsite correlation at half filling using the unrestricted Hartree-Fock method. We find that, above a certain value of correlation strength in the barrier planes, the system is an antiferromagnetic insulator, while below this value the system is gapless with no spin density wave order but still with considerable charge inhomogeneity being present across the planes. The energy spectrum is found to have multiple gaps as the correlation strength is increased. The system is insulating for values of correlation above the critical value at which the gap at half filling opens up. (C) 2011 Elsevier Ltd. All rights reserved.