We consider in detail the ground-state properties of recently introduced generalized Heisenberg models which can have several spin operators at each site and which interpolate smoothly between Heisenberg chains of different spin lengths. We show that the mappings to field-theoretical models used to describe the critical properties of the Heisenberg model remain valid in the composite-spin model. In models which interpolate between the spin-(1/2 and the spin-1 behavior, these mappings predict an extended singlet phase around the isotropic antiferromagnetic point whenever the models move away from the spin-(1/2 point. Numerical calculations on finite chains seem to confirm the existence of this singlet phase. The phase boundaries are, however, found to be independent of the interpolation parameter, and thus in disagreement with the predictions of the continuum theory, indicating its limitation.We consider in detail the ground-state properties of recently introduced generalized Heisenberg models which can have several spin operators at each site and which interpolate smoothly between Heisenberg chains of different spin lengths. We show that the mappings to field-theoretical models used to describe the critical properties of the Heisenberg model remain valid in the composite-spin model. In models which interpolate between the spin-(1/2 and the spin-1 behavior, these mappings predict an extended singlet phase around the isotropic antiferromagnetic point whenever the models move away from the spin-(1/2 point. Numerical calculations on finite chains seem to confirm the existence of this singlet phase. The phase boundaries are, however, found to be independent of the interpolation parameter, and thus in disagreement with the predictions of the continuum theory, indicating its limitation.

Physical review. B, Condensed matterOct 1, 198815 citations

Excitations and Critical Behavior in Generalized Heisenberg Spin Chains

J. C. Bonner, Gerhard H. Muller, John B. Parkinson

Springer proceedings in physicsJan 1, 19870 citations

Ground State and Finite Temperature Properties of Mixed Diamond Chains with Spins 1 and 1/2 with Single-site Anisotropy

Kazuo Hida

Ground states and ﬁnite temperature properties of mixed diamond chains with spins 1 and1/2 which has the single-site anisotropy on spin-1 sites are investigated. There are phaseswhere the ground state is a spin cluster solid, i. e. an array of uncorrelated spin-1 clustersseparated by singlet dimers. The ground state is nonmagnetic for the easy-plane anisotropy,while it is paramagnetic for the easy-axis anisotropy. Also there are the N´eel, Haldane, andlarge-D phases, where the ground state is a single spin cluster of inﬁnite size and the systemis equivalent to the spin-1 Heisenberg chain with alternating anisotropy. The longitudinal andtransverse susceptibilities and entropy are calculated at ﬁnite temperatures in the spin-cluster-solid phases. Their low temperature behaviors are sensitive to the anisotropy.KEYWORDS: mixed diamond chain, anisotropy, frustration, spin cluster solid, N´eel phase, Haldane phase,large-DphaseGround states and ﬁnite temperature properties of mixed diamond chains with spins 1 and1/2 which has the single-site anisotropy on spin-1 sites are investigated. There are phaseswhere the ground state is a spin cluster solid, i. e. an array of uncorrelated spin-1 clustersseparated by singlet dimers. The ground state is nonmagnetic for the easy-plane anisotropy,while it is paramagnetic for the easy-axis anisotropy. Also there are the N´eel, Haldane, andlarge-D phases, where the ground state is a single spin cluster of inﬁnite size and the systemis equivalent to the spin-1 Heisenberg chain with alternating anisotropy. The longitudinal andtransverse susceptibilities and entropy are calculated at ﬁnite temperatures in the spin-cluster-solid phases. Their low temperature behaviors are sensitive to the anisotropy.KEYWORDS: mixed diamond chain, anisotropy, frustration, spin cluster solid, N´eel phase, Haldane phase,large-Dphase

Jun 20, 20110 citations

Ground-state properties of antiferromagnetic anisotropic S=1 Heisenberg spin chains

D. Peters, Ian P. McCulloch, Walter Selke

Using (infinite) density-matrix renormalization-group techniques, ground-state properties of antiferromagnetic $S=1$ Heisenberg spin chains with exchange and single-site anisotropies in an external field are studied. The phase diagram is known to display a plenitude of interesting phases. We elucidate quantum phase transitions between the supersolid and spin-liquid phases as well as the spin-liquid and ferromagnetic phases. Analyzing spin-correlation functions in the spin-liquid phase, commensurate and (two distinct) incommensurate regions are identified.Using (infinite) density-matrix renormalization-group techniques, ground-state properties of antiferromagnetic $S=1$ Heisenberg spin chains with exchange and single-site anisotropies in an external field are studied. The phase diagram is known to display a plenitude of interesting phases. We elucidate quantum phase transitions between the supersolid and spin-liquid phases as well as the spin-liquid and ferromagnetic phases. Analyzing spin-correlation functions in the spin-liquid phase, commensurate and (two distinct) incommensurate regions are identified.

arXiv:1111.5547Physical Review BFeb 22, 201212 citations

Excitation spectrum of heisenberg spin chains

Vladyslav O. Cheranovskii

Theoretical and Experimental ChemistryJan 1, 19881 citation

Using (infinite) density-matrix renormalization-group techniques, ground-state properties of antiferromagnetic

S=1

Heisenberg spin chains with exchange and single-site anisotropies in an external field are studied. The phase diagram is known to display a plenitude of interesting phases. We elucidate quantum phase transitions between the supersolid and spin-liquid phases as well as the spin-liquid and ferromagnetic phases. Analyzing spin-correlation functions in the spin-liquid phase, commensurate and (two distinct) incommensurate regions are identified.