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

Abstract

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.

Authors:
 [1];  [2];  [2];  [2]
  1. Universidade Federale de Uberlandia, Brazil
  2. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Center for Nanophase Materials Sciences
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
979320
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B; Journal Volume: 81; Journal Issue: 8
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AMPLITUDES; DENSITY MATRIX; FERMIONS; FERROMAGNETISM; FLUCTUATIONS; GROUND STATES; HUBBARD MODEL; PNICTIDES; PRECURSOR; RENORMALIZATION

Citation Formats

Xavier, J. C., Alvarez, Gonzalo, Moreo, Adriana, and Dagotto, Elbio R. Coexistence of Pairing Tendencies and Ferromagnetism in a Doped Two-Orbital Hubbard Model on Two-Leg Ladders. United States: N. p., 2010. Web. doi:10.1103/PhysRevB.81.085106.
Xavier, J. C., Alvarez, Gonzalo, Moreo, Adriana, & Dagotto, Elbio R. Coexistence of Pairing Tendencies and Ferromagnetism in a Doped Two-Orbital Hubbard Model on Two-Leg Ladders. United States. doi:10.1103/PhysRevB.81.085106.
Xavier, J. C., Alvarez, Gonzalo, Moreo, Adriana, and Dagotto, Elbio R. Fri . "Coexistence of Pairing Tendencies and Ferromagnetism in a Doped Two-Orbital Hubbard Model on Two-Leg Ladders". United States. doi:10.1103/PhysRevB.81.085106.
@article{osti_979320,
title = {Coexistence of Pairing Tendencies and Ferromagnetism in a Doped Two-Orbital Hubbard Model on Two-Leg Ladders},
author = {Xavier, J. C. and Alvarez, Gonzalo and Moreo, Adriana and Dagotto, Elbio R},
abstractNote = {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.},
doi = {10.1103/PhysRevB.81.085106},
journal = {Physical Review B},
number = 8,
volume = 81,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 2010},
month = {Fri Jan 01 00:00:00 EST 2010}
}