TY - JOUR

T1 - Competition between spin exchange and correlated hopping

AU - Saiga, Y.

AU - Imada, M.

N1 - Funding Information:
One of the authors (Y.S.) is grateful to M. Oshikawa, K. Okamoto and M. Kohno for valuable discussions. Y.S. is supported by JSPS Research Fellowships for Young Scientists.

PY - 2002

Y1 - 2002

N2 - The ground-state phase diagram is numerically studied for an electronic model consisting of the spin exchange term (J) and the correlated hopping term (t3: the three-site term). This model has no single-particle hopping and the ratio of the two terms is controlled by a parameter α≡4t3/J. The case of α=1 corresponds to complete suppression of single-particle hopping in the strong-coupling limit of the Hubbard model. In one dimension, phase separation takes place below a critical value αc = 0.36-0.63 which depends on the electron density. Spin gap opens in the whole region except the phase-separated one. For α ≳ 1.2 and low hole densities, charge-density-wave correlations are the most dominant, whereas singlet-pairing correlations are the most dominant in the remaining region. The possibility of superconductivity in the two-dimensional case is also discussed, based on equal-time pairing correlations.

AB - The ground-state phase diagram is numerically studied for an electronic model consisting of the spin exchange term (J) and the correlated hopping term (t3: the three-site term). This model has no single-particle hopping and the ratio of the two terms is controlled by a parameter α≡4t3/J. The case of α=1 corresponds to complete suppression of single-particle hopping in the strong-coupling limit of the Hubbard model. In one dimension, phase separation takes place below a critical value αc = 0.36-0.63 which depends on the electron density. Spin gap opens in the whole region except the phase-separated one. For α ≳ 1.2 and low hole densities, charge-density-wave correlations are the most dominant, whereas singlet-pairing correlations are the most dominant in the remaining region. The possibility of superconductivity in the two-dimensional case is also discussed, based on equal-time pairing correlations.

KW - A. Superconductors

KW - D. Phase transitions

KW - D. Superconductivity

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U2 - 10.1016/S0022-3697(02)00037-9

DO - 10.1016/S0022-3697(02)00037-9

M3 - Article

AN - SCOPUS:0036602181

VL - 63

SP - 1531

EP - 1535

JO - Journal of Physics and Chemistry of Solids

JF - Journal of Physics and Chemistry of Solids

SN - 0022-3697

IS - 6-8

ER -