Signatures of Pairing in the Magnetic Excitation Spectrum of Strongly Correlated two-leg Ladders

ORAL

Abstract

Understanding the superconducting mechanism in cuprates and pnictides remains elusive, mainly due to the lack of well-controlled theoretical methods to calculate the doping evolution of the magnetic excitations in two dimensions. However, two-leg ladder systems have provided considerable insights in the physics of cuprates, and recent discoveries support the idea that they could also be much helpful in pnictides. In this talk I will address the following question: can we identify signatures of pairing in the magnetic excitation spectrum of two-leg ladders? I will use the density matrix renormalization group to obtain the dynamical spin structure factor of a generalized t–U–J Hubbard model1. This model includes an exchange correlation strength J independent of U, enhancing pairing tendencies that otherwise would be weak. Motivated by recent neutron scattering results2, I will present a systematic study of the magnetic excitations as a function of hole doping, Hubbard repulsion, and magnetic exchange interactions, and I will discuss the implications of our study for RIXS and neutron scattering experiments.

1A. Nocera, N. D. Patel, E. Dagotto, G. Alvarez, arXiv:1707.02626 (2017)
2G. Deng, et al. Phys. Rev. B 88, 014504 (2013)

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Presenters

  • Alberto Nocera

    • Univ. of Tennessee
    • Physics and Astronomy, University of Tennessee
    • Department of Physics and Astronomy, Univ of Tennessee, Knoxville
    • University of Tennessee

Authors

  • Alberto Nocera

    • Univ. of Tennessee
    • Physics and Astronomy, University of Tennessee
    • Department of Physics and Astronomy, Univ of Tennessee, Knoxville
    • University of Tennessee

  • Nirav Patel

    • Univ. of Tennessee
    • Physics and Astronomy, University of Tennessee

  • Elbio Dagotto

    • Univ. of Tennessee
    • Physics and Astronomy, University of Tennessee
    • Department of Physics and Astronomy, Univ of Tennessee, Knoxville
    • Department of Physics and Astronomy, University of Tennessee
    • University of Tennessee
    • University of Tennessee & Oak Ridge National Laboratory
    • Department of Physics and Astronomy, University of Tennessee, Knoxville

  • Gonzalo Alvarez

    • Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory