Period 4 stripe in the extended two-dimensional Hubbard model

We study the competition between stripe states with different periods and a uniform d-wave superconducting state in the extended two-dimensional Hubbard model at 1/8 hole doping using infinite projected entangled-pair states (iPEPS). With increasing strength of negative next-nearest neighbor hopping t′ , the preferred period of the stripe decreases. For the values of t′ predicted for cuprate high-T_c superconductors, we find stripes with a period 4 in the charge order, in agreement with experiments. Superconductivity in the period 4 stripe is suppressed at 1/8 doping. Only at larger doping, 0.18 ≲ δ < 0.25, the period 4 stripe exhibits coexisting d-wave superconducting order. The uniform d-wave state is only favored for sufficiently large positive t′.