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