Numerical renormalization-group study of the one-dimensionalt-Jmodel

The one-dimensional t-J model is investigated using the density-matrix renormalization-group (DMRG) method. We report a generalization of the DMRG method to the case of arbitrary band filling and prove a theorem with respect to the reduced density matrix that accelerates the numerical computation. Lastly, using the extended DMRG method, we present the ground-state electron momentum distribution, as well as spin- and charge-correlation functions. The 3${\mathit{k}}_{\mathit{F}}$ anomaly of the momentum distribution function discussed by Ogata and Shiba is shown to disappear as J increases. We also argue that there exists a density-independent ${\mathit{J}}_{\mathit{c}}$ beyond which the system becomes an electron solid. © 1996 The American Physical Society.