Ground-state phase diagram of the one-dimensional extended Hubbard model

We study the ground-state phase diagram of the extended Hubbard model through the Lanczos method using charge-density-wave order-parameter distribution functions and finite-size scaling. We confirm the presence of a tricritical point, and estimate the phase boundary to occur at V=2.920.04 at U=5.5, and at V=1.65-0.05+0.10 at U=3.0. We estimate the tricritical point to occur above U=3.5. Despite the restriction to small lattices, the increased accuracy of the Lanczos approach appears to provide a more precise estimate of the phase boundary and tricritical point than use of the Monte Carlo simulation.