Session T21: Magnetic Ordering and Dynamics in Cuprates

2:30 PM–5:30 PM, Wednesday, February 29, 2012
Room: 254A

Sponsoring Unit: DCMP
Chair: Anna Llobet, Los Alamos National Laboratory

Abstract ID: BAPS.2012.MAR.T21.3

Abstract: T21.00003 : Novel magnetic excitations in the high-temperature superconductor HgBa$_{2}$CuO$_{4+ \delta }$

2:54 PM–3:06 PM

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Authors:

  Mun Chan
    (University of Minnesota)

  Yuan Li
    (Max Planck Institute for Solid State Research, Germany)

  V. Bal\`{e}dent
    (Laboratoire L\`{e}on Brillouin)

  N. Bari\v{s}i\`{c}
    (University of Minnesota)

  K. Hradil
    (Forschungsneutronenquelle Heinz Maier-Leibnitz, Germany)

  Yangmu Li
    (University of Minnesota)

  R.A. Mole
    (Forschungsneutronenquelle Heinz Maier-Leibnitz, Germany)

  Y. Sidis
    (Laboratoire L\`{e}on Brillouin)

  P. Steffens
    (Institut Laue Langevin, France)

  G. Yu
    (University of Minnesota)

  X. Zhao
    (Jilin University, China)

  P. Bourges
    (Laboratoire L\`{e}on Brillouin)

  M. Greven
    (University of Minnesota)

We report on the observation of novel magnetic excitations in the pseudogap phase of the cuprate superconductor HgBa$_{2}$CuO$_{4+\delta }$ (Hg1201) using neutron scattering, and on their relationship with antiferromagnetic (AF) fluctuations. Following polarized neutron diffraction experiments that demonstrated a novel (q=0) magnetic order in the pseudogap phase [B. Fauqu\'{e} \textit{et al.} PRL 96, 197001 (2006); Y. Li \textit{et al.}, Nature 455, 372 (2008)], our inelastic measurements revealed two weakly-dispersive magnetic excitation branches in Hg1201 [Y. Li \textit{et al.}, Nature 468, 283 (2010), and preprint]. These excitations are observed in the pseudogap phase and appear to be associated with the q=0 magnetic order. In our optimally-doped sample, the magnetic resonance occurs at the dispersion maximum of the higher-energy branch. In under-doped Hg1201, the two excitation branches exhibit local intensity maxima at q$_{AF}$, and we find evidence for an hourglass dispersion associated with the lower branch. These results reveal a profound connection between the novel excitations and the conventional AF fluctuations.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2012.MAR.T21.3