Quantum oscillations in a bilayer with broken mirror symmetry: a minimal model for YBa$_2$Cu$_3$O$_{6 + \delta}$

ORAL

Abstract

Using an exact numerical solution and semiclassical analysis, we investigate quantum oscillations (QOs) in a model of a bilayer system with an anisotropic (elliptical) electron pocket in each plane. Key features of QO experiments in the high temperature superconducting cuprate YBCO can be reproduced by such a model, in particular the pattern of oscillation frequencies (which reflect ``magnetic breakdown'' between the two pockets) and the polar and azimuthal angular dependence of the oscillation amplitudes. However, the requisite magnetic breakdown is possible only under the assumption that the horizontal mirror plane symmetry is spontaneously broken and that the bilayer tunneling, $t_\perp$, is substantially renormalized from its `bare' value. Under the assumption that $t_{\perp} = \tilde{Z}t_\perp^{(0)}$, where $\tilde{Z}$ is a measure of the quasiparticle weight, this suggests that $\tilde{Z} \lesssim 1/20$. Detailed comparisons with new YBa$_2$Cu$_3$O$_{6.58}$ QO data, taken over a very broad range of magnetic field, confirm specific predictions made by the breakdown scenario.

*Supported in part by the US DOE, Office of Basic Energy Sciences under contract DE-AC02-76SF00515 (A.V.M.),the US DOE Office of Basic Energy Sciences ``Science at 100 T," (B.J.R.) and the National Science Foundation Grant No. DMR 1265593 (S.A.K., YZ)

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Authors

  • Akash Maharaj

    • Stanford University

  • Yi Zhang

    • Stanford University

  • Brad Ramshaw

    • National High Magnetic Field Laboratory, Los Alamos National Laboratory,
    • National High MagneticField Laboratory, Los Alamos National Laboratory, Los Alamos, NM, USA.

  • Steven Kivelson

    • Stanford University
    • Department of Physics, Stanford University
    • Stanford Univ