3 research outputs found
Competing orders in a magnetic field: spin and charge order in the cuprate superconductors
We describe two-dimensional quantum spin fluctuations in a superconducting
Abrikosov flux lattice induced by a magnetic field applied to a doped Mott
insulator. Complete numerical solutions of a self-consistent large N theory
provide detailed information on the phase diagram and on the spatial structure
of the dynamic spin spectrum. Our results apply to phases with and without
long-range spin density wave order and to the magnetic quantum critical point
separating these phases. We discuss the relationship of our results to a number
of recent neutron scattering measurements on the cuprate superconductors in the
presence of an applied field. We compute the pinning of static charge order by
the vortex cores in the `spin gap' phase where the spin order remains
dynamically fluctuating, and argue that these results apply to recent scanning
tunnelling microscopy (STM) measurements. We show that with a single typical
set of values for the coupling constants, our model describes the field
dependence of the elastic neutron scattering intensities, the absence of
satellite Bragg peaks associated with the vortex lattice in existing neutron
scattering observations, and the spatial extent of charge order in STM
observations. We mention implications of our theory for NMR experiments. We
also present a theoretical discussion of more exotic states that can be built
out of the spin and charge order parameters, including spin nematics and phases
with `exciton fractionalization'.Comment: 36 pages, 33 figures; for a popular introduction, see
http://onsager.physics.yale.edu/superflow.html; (v2) Added reference to new
work of Chen and Ting; (v3) reorganized presentation for improved clarity,
and added new appendix on microscopic origin; (v4) final published version
with minor change
Spin dynamics in the stripe phase of high-T c cuprates with the modulation of superconducting order
Possible superconducting order modulation and its effect on the spin susceptibility in the coexisting phase of the stripe and
superconducting orders are investigated. It is shown that the superconducting order modulation is mainly caused by the
spin-domain-derived scattering, while the charge-domain-derived scattering tends to suppress it in a wide parameter region.
The modulation leads to a two-peak structure in the spin excitation spectrum, which is qualitatively consistent with the
recent experimental observations in La2-xSrxCuO4. This result suggests the importance of the superconducting
order modulation for the understanding of the multiform spin excitations in these cuprate superconductors