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Phys. Rev. B 54, R3746–R3749 (1996)

Phase separation and the existence of superconductivity in a one-dimensional copper-oxygen model

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A. W. Sandvik
National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, Florida 32306

A. Sudbø
Department of Physics, Norwegian University of Science and Technology, N-7034 Trondheim, Norway

Received 21 February 1996; revised 9 May 1996; published in the issue dated 1 August 1996

The phase-separation instability occurring with increasing nearest-neighbor repulsion V in a two-band Hubbard model (CuO chain) is discussed. Quantum Monte Carlo simulations indicate that this transition is strongly discontinuous if the filling fraction n is close to 1 (half-filled lower band). Spin-density-wave fluctuations then dominate before phase separation. Superconducting fluctuations dominate in the neighborhood of phase separation only at considerably higher doping levels, where the transition to the phase-separated state is much smoother.

© 1996 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.54.R3746
DOI:
10.1103/PhysRevB.54.R3746
PACS: