Quantum lattice fluctuations in the one-dimensional molecular-crystal model with Coulomb repulsion

Journal Article · Thu Mar 01 00:00:00 EST 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.41.4723· OSTI ID:6847373

Zheng, H ^[1]

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1. Chinese Center of Advanced Science and Technology (World Laboratory), P.O. Box 8730, Beijing, People's Republic of China (CN) Department of Applied Physics, Shanghai Jiao Tong University, Shanghai, People's Republic of China (CN)

The effect of quantum lattice fluctuations on the ground state of a half-filled-band one-dimensional molecular-crystal model with on-site ({ital U}) and nearest-neighbor ({ital V}) Coulomb repulsion is investigated. The nonadiabatic effects due to finite phonon frequency {omega} are treated through a variational polaron wave function. The electronic correlations are decoupled by a Hartree-Fock approximation. Our variational approach gives a rather good description of the continuous variation of the dimerization, which is in good agreement with that of the Monte Carlo simulations, as functions of {ital U}, {ital V}, and {omega}. However, the Hartree-Fock theory predicts a fictitious long-range spin-density-wave order and a discontinuous transition between it and the charge-density-wave (CDW) state. These are somewhat different from the results of numerical simulations. Furthermore, we propose a valence-bonding (VB) state for describing the short-range antiferromagnetic correlation for intermediate values of {ital U} and {ital V} and determine the transition point between the VB state and the CDW state, which is in good agreement with that of the numerical simulations. The effect of quantum lattice fluctuations on the transition point is also discussed.

• OSTI ID: 6847373
• Journal Information: Physical Review, B: Condensed Matter; (USA), Vol. 41:7; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRYSTAL MODELS
ELECTRON-PHONON COUPLING
MOLECULAR CRYSTALS
COULOMB FIELD
ANTIFERROMAGNETISM
CHARGE DENSITY
ELECTRON CORRELATION
FLUCTUATIONS
HARTREE-FOCK METHOD
MONTE CARLO METHOD
SPIN WAVES
CORRELATIONS
CRYSTALS
ELECTRIC FIELDS
MAGNETISM
MATHEMATICAL MODELS
VARIATIONS
656002* - Condensed Matter Physics- General Techniques in Condensed Matter- (1987-)