Phase diagram of the Holstein-Hubbard two-leg ladder using a functional renormalization-group method
- Author(s): Tam, Ka-Ming
- Tsai, Shan-Wen
- Castro Neto, Antonio H.
- Campbell, David K.
- et al.
Published Web Locationhttp://link.aps.org/abstract/PRB/v75/e195119
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.