Two observable features of the staggered-flux phase at nonzero doping
- Department of Physics, University of British Columbia, 6224 Agriculture Road, Vancouver, British Columbia, Canada V6T-2A6 (CA)
- Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853-2501 (USA)
- Department of Physics, University of British Columbia, 6224 Agriculture Road, Vancouver, British Columbia (Canada)
We investigate whether the staggered-flux phase (SFP) is realized in slightly doped phases of the Cu-O high-{ital T}{sub {ital c}} superconductors. Using a mean-field solution of the {ital t}-{ital J} model, we calculate the size of circulating currents in the CuO{sub 2} planes. For realistic parameters we find nonzero currents when the doping {delta}{lt}0.12. Taking into account structural details, we calculate the physical magnetic-field strength and the neutron-scattering cross section. The static field at the muon site varies between 0 and 100 G depending mainly on doping but with additional complications being the size of the Wannier functions, temperature, screening, localization, and the mean-field-approximation itself. These fields are not detected in muon-spin-relaxation experiments but cannot be ruled out both because of the aforementioned complications and because at low doping the muon is also affected by residual quasistatic spin moments. Neutrons scattering off orbital moments of the SFP exhibit a Bragg peak at wave vector ({pi}/{ital a},{pi}/{ital a}) even at nonzero doping; however, this peak is perhaps 70 times weaker than that produced by static spin moments in a fully Neel ordered phase and is therefore difficult to observe. The absence of quasistatic spin moments in our description conflicts with neutron experiments on lightly doped samples. The inelastic spin structure does, however, exhibit a split peak at wave vector ({pi}/{ital a},{pi}/{ital a}) in qualitative agreement with neutron experiments on superconducting La{sub 2{minus}{ital x}}Sr{sub {ital x}}CuO{sub 4} samples but additional structure along the ({ital Q}{sub {ital x}},0) and (0,{ital Q}{sub {ital y}}) directions has not been seen. The absence of magnetic fields when {delta}{gt}0.12 is consistent with the limits set by the muon experiments on superconducting samples.
- OSTI ID:
- 5831444
- Journal Information:
- Physical Review, B: Condensed Matter; (USA), Vol. 43:4; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
CUPRATES
MAGNETIC FLUX
HIGH-TC SUPERCONDUCTORS
CRYSTAL DOPING
MEAN-FIELD THEORY
MUON SPIN RELAXATION
NEUTRON DIFFRACTION
COHERENT SCATTERING
COPPER COMPOUNDS
DIFFRACTION
OXYGEN COMPOUNDS
RELAXATION
SCATTERING
SUPERCONDUCTORS
TRANSITION ELEMENT COMPOUNDS
656100* - Condensed Matter Physics- Superconductivity
360204 - Ceramics
Cermets
& Refractories- Physical Properties