arXiv:0804.4810 · Physical Review B
Phase diagram of the t−U−J1−J2 chain at half filling
X.Y Huang, E. Szirmai, Florian Gebhard, Jenő Sólyom, R. M. Noack
Abstract
We investigate the Hubbard chain at half band filling with additional nearest-neighbor and next-nearest-neighbor spin exchange ${J}_{1}$ and ${J}_{2}$ using bosonization and the density-matrix renormalization group. For ${J}_{2}=0$ we find a spin-density-wave phase for all positive values of the Hubbard interaction $U$ and the Heisenberg exchange ${J}_{1}$. A frustrating spin exchange ${J}_{2}$ induces a bond-order-wave phase. For some values of ${J}_{1}$, ${J}_{2}$, and $U$, we observe a spin-gapped metallic Luther-Emery phase.