Abstract
We derive exactly all Green’s functions for the two-site Hubbard-Holstein model. We then study the bipolaron phase diagram, with emphasis on its unbinding into two polarons and on the crossover from a two-site to a one-site bipolaron. The results are relevant for infinite-size systems.
- Received 14 November 2006
DOI:https://doi.org/10.1103/PhysRevB.75.081101
©2007 American Physical Society