Singlet quantum phases and magnetization of the frustrated spin-1/2 ladder with ferromagnetic (F) exchange in legs and alternating F-AF exchange in rungs

Monalisa Chatterjee; Manoranjan Kumar; ZoltÃ¡n G. Soos

paper

Singlet quantum phases and magnetization of the frustrated spin-1/2 ladder with ferromagnetic (F) exchange in legs and alternating F-AF exchange in rungs

arXiv:2305.12884

Abstract

The magnetization $M (h)$ is used to identify three singlet quantum phases of the ladder with isotropic exchange interactions. The Dimer phase with frustrated F exchanges in rungs and legs has a first-order $M (h)$ transition at $0$ K from singlet to ferromagnetic at the saturation field $h_{s}$ . The Haldane-DAF phase with strong F exchange in rungs and net AF exchange between rungs has continuous $M (h)$ and is adiabatically connected to the $S = 1$ Heisenberg AF chain. The AF phase with strong F exchange in legs and net AF exchange between legs has continuous $M (h)$ and is adiabatically connected to the spin-1/2 $J_{1} - J_{2}$ model with $J_{1} > 0$ and $J_{2} < 0$ . All three singlet phases have finite gaps to the lowest triplet state.

6 pages, 4 figues