2002/10/21 by M. C. Refolio, Refolio, M. C., Javier Sancho +4
Physics and Astronomy · #Opinion Dynamics and Social Influence #Physics of Superconductivity and Magnetism #Theoretical and Computational Physics #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.cond-mat/0210462
arxiv created 2002/10/21 · arxiv updated 2009/11/30
The one-electron spectral-weight function of the half-filled ionic Hubbard model is calculated by means of Quantum Monte Carlo. A metallic regimen occurs between two values of the coupling constant (Hubbard U) U1 < U2 . The system is a band insulator below U1, and an increasingly antiferromagnetic (AF) insulator above U2 evolving into a Mott insulator as U tends to infinity . The intermediate regimen which is both AF and dimerized, is caused by a two-peak structure at k = 0,5 pi (the Fermi surface). As U increases both peaks approach each other, overlap, and separate again, the system becoming metallic in the overlap region.