Using a functional renormalization-group method, we obtain the phase diagram of the two-leg ladder system within the Holstein-Hubbard model, which includes both electron-electron and electron-phonon interactions. Our renormalization-group technique allows us to analyze the problem for both weak and strong electron-phonon couplings. We show that, in contrast to results from conventional weak-coupling studies, electron-phonon interactions can dominate electron-electron interactions, and retardation effects play an important role on the phase diagram. © 2007 The American Physical Society.
Publication Source (Journal or Book title)
Physical Review B - Condensed Matter and Materials Physics
Tam, K., Tsai, S., Campbell, D., & Castro Neto, A. (2007). Phase diagram of the Holstein-Hubbard two-leg ladder using a functional renormalization-group method. Physical Review B - Condensed Matter and Materials Physics, 75 (19) https://doi.org/10.1103/PhysRevB.75.195119