Penson-Kolb-Hubbard model: A study of the competition between single-particle and pair hopping in one dimension

Journal Article · Thu Jul 15 00:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.2063· OSTI ID:6324797

Hui, A ^[1]; Doniach, S ^[2]

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1. Department of Physics, Stanford University, Stanford, California 94305 (United States)
2. Department of Applied Physics, Stanford University, Stanford, California 94305 (United States)

In this paper, we present a study of the ground-state phase diagram of a one-dimensional quantum chain, the Penson-Kolb-Hubbard model, H=[minus][summation][sub i],[eta]=[plus minus]1,[sigma] ([ital tc][sub [ital i]+[eta][sigma]][sup [dagger]][ital c][sub [ital i][sigma]]+[ital Vc][sub [ital i]+[eta][up arrow]][sup [dagger]][ital c][sub [ital i]+[eta][down arrow]][sup [dagger]][ital c][sub [ital i][down arrow]][ital c[ital i][up arrow]])+ [summation][sub [ital i]] U[ital n][sub [ital i][up arrow]][ital n][ital i][down arrow] at half filling. We have examined the system using exact diagonalization for samples of up to 12 sites and employed two techniques, eigenprojection decomposition and twisted-boundary conditions, in analyzing the data. These techniques allow us to characterize the ground state in a manner insensitive to changes in sample size and provide us with a clean way to visualize the physics. When used with the correct'' order parameter, qualitative features emerge even for sample sizes as small as six sites. We find that the second-order charge-density-wave--spin-density-wave transition in the weak-coupling limit ([ital t][much gt][ital U][similar to]2[ital V]) turns into a first-order superconducting--antiferromagnetic transition in the strong-coupling regime [[ital t][much lt][ital U][similar to](4/[pi])[ital V]]. We also observe evidence of a charge-density-wave--superconducting transition in the parameter range ([ital t][similar to][ital V][much gt][ital U]). These three transition lines meet together at a tricritical point at ([ital t]:[ital U]:[ital V])[similar to](0.04:0.54:0.42). A naive renormalization-group analysis in the intermediate-coupling regime produces results consistent with this conclusion.

• OSTI ID: 6324797
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 48:4; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
HIGH-TC SUPERCONDUCTORS
HUBBARD MODEL
PHASE DIAGRAMS
ANTIFERROMAGNETISM
GROUND STATES
ONE-DIMENSIONAL CALCULATIONS
ORDER PARAMETERS
SPIN WAVES
CRYSTAL MODELS
DIAGRAMS
ENERGY LEVELS
MAGNETISM
MATHEMATICAL MODELS
SUPERCONDUCTORS
665411* - Basic Superconductivity Studies- (1992-)