arXiv:1709.00245 · Physical review. B./Physical review. B
Doping dependence of ordered phases and emergent quasiparticles in the doped Hubbard-Holstein model
Christian B. Mendl, Elizabeth Nowadnick, Edwin W. Huang, Steven Johnston, Brian Moritz, Thomas Devereaux
Abstract
We present determinant quantum Monte Carlo simulations of the hole-doped single-band Hubbard-Holstein model on a square lattice, to investigate how quasiparticles emerge when doping a Mott insulator (MI) or a Peierls insulator (PI). The MI regime at large Hubbard interaction $U$ and small relative e-ph coupling strength $\ensuremath{\lambda}$ is quickly suppressed upon doping, by drawing spectral weight from the upper Hubbard band and shifting the lower Hubbard band towards the Fermi level, leading to a metallic state with emergent quasiparticles at the Fermi level. On the other hand, the PI regime at large $\ensuremath{\lambda}$ and small $U$ persists out to relatively high doping levels. We study the evolution of the $d$-wave superconducting susceptibility with doping, and find that it increases with lowering temperature in a regime of intermediate values of $U$ and $\ensuremath{\lambda}$.