Existence of an Intermediate Metallic Phase at the SDW-CDW Crossover Region in the One-Dimensional Holstein-Hubbard Model at Half-Filling

Figure 1

(Color online) Ground-state energy per site as a function of 𝑈 for 𝛼=1 and three cases of 𝑡/𝜔₀=0.1, 0.2, and 0.4.