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Magnetic Coherence in Cuprate Superconductors

Dirk K. Morr·David Pines
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Abstract

Recent inelastic neutron scattering (INS) experiments on La$_{2-x}$Sr$_x$CuO$_4$ observed a {\it magnetic coherence effect}, i.e., strong frequency and momentum dependent changes of the spin susceptibility, $χ''$, in the superconducting phase. We show that this effect is a direct consequence of changes in the damping of incommensurate antiferromagnetic spin fluctuations due to the appearance of a d-wave gap in the fermionic spectrum. Our theoretical results provide a quantitative explanation for the weak momentum dependence of the observed spin-gap. Moreover, we predict {\bf (a)} a Fermi surface in La$_{2-x}$Sr$_x$CuO$_4$ which is closed around $(π,π)$ up to optimal doping, and {\bf (b)} similar changes in $χ''$ for all cuprates with an incommensurate magnetic response.

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Dirk K. Morr, David Pines. 2000-04-13. Magnetic Coherence in Cuprate Superconductors. https://doi.org/10.1103/physrevb.61.r6483

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