Coexistence of Pairing Tendencies and Ferromagnetism in a Doped Two-Orbital Hubbard Model on Two-Leg Ladders

Journal Article · Fri Jan 01 04:00:00 EST 2010 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.81.085106· OSTI ID:979320

Xavier, J. C. ^[1]; Alvarez, Gonzalo ^[2]; Moreo, Adriana ^[2]; Dagotto, Elbio R ^[2]

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1. Universidade Federale de Uberlandia, Brazil
2. ORNL

Using the Density Matrix Renormalization Group and two-leg ladders, we investigate an electronic two-orbital Hubbard model including plaquette-diagonal hopping amplitudes. Our goal is to search for regimes where charges added to the undoped state form pairs, presumably a precursor of a superconducting state. For the electronic density {rho}=2, i.e., the undoped limit, our investigations show a robust ({pi},0) antiferromagnetic ground state, as in previous investigations. Doping away from {rho}=2 and for large values of the Hund coupling J, a ferromagnetic region is found to be stable. Moreover, when the interorbital on-site Hubbard repulsion is smaller than the Hund coupling, i.e., for U' < J in the standard notation of multiorbital Hubbard models, our results indicate the coexistence of pairing tendencies and ferromagnetism close to {rho}=2. These results are compatible with previous investigations using one-dimensional systems. Although further research is needed to clarify if the range of couplings used here is of relevance for real materials, such as superconducting heavy fermions or pnictides, our theoretical results address a possible mechanism for pairing that may be active in the presence of short-range ferromagnetic fluctuations.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 979320
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 8 Vol. 81; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AMPLITUDES
DENSITY MATRIX
FERMIONS
FERROMAGNETISM
FLUCTUATIONS
GROUND STATES
HUBBARD MODEL
PNICTIDES
PRECURSOR
RENORMALIZATION