Competition of pairing and Peierls–charge-density-wave correlations in a two-dimensional electron-phonon model

Monte Carlo simulations are used to investigate the competition between superconducting and Peierls–charge-density-wave (CDW) correlations in a two-dimensional electron-phonon system. The dependence of these correlations on the band filling 〈n〉, phonon frequency ${\omega }_0$, and electron-phonon coupling g is examined. The Peierls-CDW correlations are favored as 〈n〉 moves towards half-filling, ${\omega }_0$ decreases, and g increases. When the Peierls-CDW correlations are weak, the Monte Carlo results for the superconducting correlations are found to be in excellent agreement with the results obtained using the well-known Eliashberg approximation.