Unified phase diagram of models exhibiting neutral-ionic transition
arXiv:cond-mat/0511082 · doi:10.1103/PhysRevB.73.165124
Abstract
We have studied the neutral-ionic transition in organic mixed-stack compounds. A unified model has been derived which, in limiting cases, is equivalent to the models proposed earlier, the donor-acceptor model and the ionic Hubbard model. Detailed numerical calculations have been performed on this unified model with the help of the density-matrix renormalization-group (DMRG) procedure calculating excitation gaps, ionicity, lattice site entropy, two-site entropy, and the dimer order parameter on long chains and the unified phase diagram has been determined.
11 pages, 8 figures