Numerical Study of a Superconductor-Insulator Transition in a Half-Filled Hubbard Chain with Distant Transfers

The ground state of a one-dimensional Hubbard model having the next-nearest neighbor hopping (t') as well as the nearest-neighbor one (t) is numerically investigated at half-filling. A quantum Monte Carlo result shows a slowly decaying pairing correlation for a sizeable interaction strength (U ≤ 2t), while the system is shown to become insulating for yet larger U>UC~ 3t from a direct evaluation of the charge gap with the density-matrix renormalization group method. The results are consistent with Fabrizio's recent weak-coupling theory which suggests a transition from a superconductor into an insulator at a finite U.