We study a frustrated mixed spin chain with side chains, where the spin species and the exchange interactions are spatially varied. A nonlinear $\ensuremath{\sigma}$ model method is formulated for this model, and a phase diagram with two disordered spin-gap phases is obtained for typical cases. Among them, we examine the case with a main chain, which consists of an alternating array of spin-1 and spin- $\frac{1}{2}$ sites, and side chains, each of which consists of a single spin- $\frac{1}{2}$ site, in great detail. Based on numerical, perturbational, and variational approaches, we propose a singlet cluster solid picture for each phase, where the ground state is expressed as a tensor product of local singlet states.We study a frustrated mixed spin chain with side chains, where the spin species and the exchange interactions are spatially varied. A nonlinear $\ensuremath{\sigma}$ model method is formulated for this model, and a phase diagram with two disordered spin-gap phases is obtained for typical cases. Among them, we examine the case with a main chain, which consists of an alternating array of spin-1 and spin-$\frac{1}{2}$ sites, and side chains, each of which consists of a single spin-$\frac{1}{2}$ site, in great detail. Based on numerical, perturbational, and variational approaches, we propose a singlet cluster solid picture for each phase, where the ground state is expressed as a tensor product of local singlet states.

arXiv:0710.3457Physical Review BApr 3, 200810 citations

Disordered Quantum Spin Chains with Long-Range Antiferromagnetic Interactions

N. Moure, Hyun‐Yong Lee, Stephan Haas +2 more

Bulletin of the American Physical SocietyMar 8, 20180 citations

Frustration-induced quantum phases in mixed spin chain with frustrated side chains

Kazuo Hida, Ken'ichi Takano

A mixed Heisenberg spin chain with frustrated side chains is investigated by numerical and perturbational calculations. A frustration-induced quantum partially polarized ferrimagnetic phase and a nonmagnetic spin quadrupolar phase are found adjacent to the conventional Lieb-Mattis-type ferrimagnetic phase or the nonmagnetic singlet cluster solid phases. The partially polarized ferrimagnetic phase has an incommensurate spin structure. Similar structures are commonly found in other frustration-induced partially polarized ferrimagnetic phases. Numerical results also suggest a series of almost critical nonmagnetic ground states in a highly frustrated regime if the side chain spins weakly couple to the main chain.A mixed Heisenberg spin chain with frustrated side chains is investigated by numerical and perturbational calculations. A frustration-induced quantum partially polarized ferrimagnetic phase and a nonmagnetic spin quadrupolar phase are found adjacent to the conventional Lieb-Mattis-type ferrimagnetic phase or the nonmagnetic singlet cluster solid phases. The partially polarized ferrimagnetic phase has an incommensurate spin structure. Similar structures are commonly found in other frustration-induced partially polarized ferrimagnetic phases. Numerical results also suggest a series of almost critical nonmagnetic ground states in a highly frustrated regime if the side chain spins weakly couple to the main chain.

arXiv:0805.3604Physical Review BAug 11, 200831 citations

Ground States of a Disordered Frustrated Quantum Dimer Magnet

Alexander T. Hristov, M. C. Shapiro, I. R. Fisher +8 more

Bulletin of the American Physical SocietyMar 6, 20150 citations

\frac{1}{2}

sites, and side chains, each of which consists of a single spin-

\frac{1}{2}

site, in great detail. Based on numerical, perturbational, and variational approaches, we propose a singlet cluster solid picture for each phase, where the ground state is expressed as a tensor product of local singlet states.