Effect of Interchain Hopping on Nonequivalent Hubbard Chains

Yoshikazu Suzumura, E. Orignac

E. Orignac, Yoshikazu Suzumura

H. Yoshizumi, T. Tohyama, T. Morinari

Motivated by the presence of different orders in multilayered high-temperature superconductors, we examine a model consisting of nonequivalent two Hubbard chains coupled by interchain hopping by using the density-matrix renormalization group (DMRG) and a mean-field theory. As an example, we consider a system with noninteracting chain without order and a Hubbard chain with strong antiferromagnetic (AF) spin-density-wave correlation. We find that the magnitude of the interchain hopping controls the strength of induced AF correlation as well as that of original one. It is also found that the induced AF correlation decreases with increasing the magnitude of the original correlation. Implications to the multilayered system are discussed.

Hiroyuki Yoshizumi, Takami Tohyama, Takao Morinari

Motivated by the presence of different orders in multilayered high-temperature superconductors, we examine a model consisting of nonequivalent two Hubbard chains coupled by interchain hopping by using the density-matrix renormalization group (DMRG) and a mean-field theory. As an example, we consider a system with noninteracting chain without order and a Hubbard chain with strong antiferromagnetic (AF) spin-density-wave correlation. We find that the magnitude of the interchain hopping controls the strength of induced AF correlation as well as that of original one. It is also found that the induced AF correlation decreases with increasing the magnitude of the original correlation. Implications to the multilayered system are discussed. Recently the coexistence of antiferromagnetism and superconductivity has been reported in multilayered high-Tc cuprate superconductors from nuclear magnetic resonance experiments. 1),2) In the superconductors, there are different layers whose carrier concentrations are unequal. When the concentration is small (large), antiferromagnetic

Michele Fabrizio, Alberto Parola, Erio Tosatti

The T=0 phase diagram for two Hubbard chains with interchain hopping ${\mathit{t}}_{\mathrm{\ensuremath{\perp}}}$ and on-site repulsion U is derived within a renormalization-group (RG) approach. We explicitly allow for renormalization of the Fermi momenta. A nonzero ${\mathit{t}}_{\mathrm{\ensuremath{\perp}}}$ drives the chains towards strong coupling, and only for large ${\mathit{t}}_{\mathrm{\ensuremath{\perp}}}$ is a Luttinger liquid recovered. By use of weak-coupling RG, a qualitative picture of the phase diagram can be obtained. Our calculations show two different strong-coupling regimes: one with nonvanishing effective interchain hopping (〈${\mathit{t}}_{\mathrm{\ensuremath{\perp}}}$〉\ensuremath{\ne}0), not confining, for small U, and another with 〈${\mathit{t}}_{\mathrm{\ensuremath{\perp}}}$〉=0, confining, for large U. Numerical diagonalizations for a small cluster support the RG results.

Cosima Schuster, Philipp Brune, Ulrich Eckern