Frustrated spin-Peierls chains

We study the phase diagram, ground-state properties, and excitation gaps of a frustrated spin-Peierls chain, i.e., a spin-Peierls chain with both nearest-neighbor exchange ${\mathit{J}}_1$ and next-nearest-neighbor exchange ${\mathit{J}}_2$. The phase diagram is calculated using a bosonization renormalization-group method. We propose a bond-operator mean-field approximation to calculate the ground-state properties and excitation gaps.