Magnetism and pairing in Hubbard bilayers

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.51.15540· OSTI ID:54955

dos Santos, R R ^[1]

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1. Instituto de Fisica, Universidade Federal Fluminense, 24210-340 Niteroi, Rio de Janeiro (Brazil)

We study the Hubbard model on a bilayer with repulsive on-site interactions {ital U} in which fermions undergo both intraplane ({ital t}) and interplane ({ital t}{sub {ital z}}) hopping. This situation is what one would expect in high-temperature superconductors such as YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital y}}, with two adjacent CuO{sub 2} planes. Magnetic and pairing properties of the system are investigated through quantum Monte Carlo simulations for both half- and quarter-filled bands. We find that in all cases interplanar pairing with {ital d}{sub {ital x}}{sup 2}{minus}{ital z}{sup 2} symmetry is dominant over planar pairing with {ital d}{sub {ital x}}{sup 2}{minus}{ital y}{sup 2} symmetry, and that for a large enough {ital t}{sub {ital z}} pair formation is possible through antiferromagnetic correlations. However, another mechanism is needed to make these pairs condense into a superconducting state at lower temperatures. We identify the temperature for pair formation with the spin-gap crossover temperature.

• OSTI ID: 54955
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 21 Vol. 51; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CRITICAL TEMPERATURE
HIGH-TC SUPERCONDUCTORS
HUBBARD MODEL
MAGNETISM
MONTE CARLO METHOD
PAIRING INTERACTIONS