Quantum Phase Diagram of One-Dimensional Spin and Hubbard Models with Transitions to Bond Order Wave Phases

Kumar, Manoranjan and Ramasesha, S and Soos, Zoltan G (2013) Quantum Phase Diagram of One-Dimensional Spin and Hubbard Models with Transitions to Bond Order Wave Phases. In: CROATICA CHEMICA ACTA, 86 (4). pp. 407-417.

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Abstract

Similar quantum phase diagrams and transitions are found for three classes of one-dimensional models with equally spaced sites, singlet ground states (GS), inversion symmetry at sites and a bond order wave (BOW) phase in some sectors. The models are frustrated spin-1/2 chains with variable range exchange, half-filled Hubbard models with spin-independent interactions and modified Hubbard models with site energies for describing organic charge transfer salts. In some range of parameters, the models have a first order quantum transition at which the GS expectation value of the sublattice spin < S-A(2)> of odd or even-numbered sites is discontinuous. There is an intermediate BOW phase for other model parameters that lead to two continuous quantum transitions with continuous < S-A(2)>. Exact diagonalization of finite systems and symmetry arguments provide a unified picture of familiar 1D models that have appeared separately in widely different contexts.

Item Type:	Journal Article
Publication:	CROATICA CHEMICA ACTA
Publisher:	CROATIAN CHEMICAL SOC
Additional Information:	Copyright for this article belongs to the CROATIAN CHEMICAL SOC, CROATIA
Keywords:	bond order wave phases; quantum phase transitions; frustrated spin chains; extended Hubbard models; neutral-ionic transition models
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	25 Feb 2014 10:15
Last Modified:	25 Feb 2014 10:15
URI:	http://eprints.iisc.ac.in/id/eprint/48468

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