Enhancement of anisotropic electron–phonon coupling in the cuprates

Abstract: Using quantum Monte Carlo techniques, we study the effects of electronic correlations on the electron–phonon coupling in a two-dimensional t–t′–U Hubbard model. We consider a momentum-dependent bare electron–phonon coupling, i.e., the electronic coupling to the B1g oxygen bond-buckling phonon. We find that the on-site Coulomb interaction U acts to effectively enhance the electron–phonon coupling at all electron- and phonon-momenta. Our numerical simulations are in good agreement with the results of functional renormalization group calculations. On the other hand, the forward scattering process near the anti-node is enhanced more than near the nodal region, leading to an enhancement of anisotropic electron–phonon coupling. Our results support the interpretation of the bosonic renormalization effects seen in angle resolved photoemission spectroscopy as electronic coupling to the B1g oxygen bond-buckling phonon. [Copyright &y& Elsevier]