Domain wall structures in the two-dimensional Hubbard model with long-range Coulomb interaction

The structure and stability of partially filled domain walls is investigated in the two-dimensional Hubbard model supplemented with a long-range Coulomb interaction. Using an unrestricted Gutzwiller variational approach, we show that the strong local interaction favors charge segregation in stripe domain walls. This approach supports the stabilization of half-filled walls for commensurate doping and large values of U even without the long-range part in contrast to results of Hartree-Fock calculations. Inclusion of the long-range interaction favors the formation of half-filled vertical stripes also in the intermediate U regime. These walls are characterized by a period doubling due to the charge and a period quadrupling due to the spins along the wall. We find that, as well as the underlying lattice structure, there is also an electronic stabilization mechanism for half-filled vertical domain walls in La1.6-xNd0.4SrxCuO4.