Spin-Hole Model with Magnetic Vortex-Antivortex Pairing Mechanism for Doped La2CuO4
The introduction of charge carriers in La2CuO4 can be achieved either by raising oxygen stoichiometry or by cation substitution, typically via the replacement of La+3 by Sr+2 or Ba+2 .1 The presence of charge carriers , which appear as electron holes on the CuO2 planes, has a profound effect on the properties of the system. Increasing their numbers beyond a low-lying threshold ( x≈0.06 in La2−xSrxCuO4) transforms the initial insulating (I) (and antiferromagnetic (AF) at low temperature) state into a metallic (M) ( superconductive (SC) at low temperature) state, and this exhibits an unusual, and not yet fully characterized, magnetic behavior .2 Doping induces, too, structural changes, the most aparent of which is a transformation from an orthorhombic (O) to a tetragonal (T) structure observable at temperatures as high as 530 K when close to the undoped limit. 1,2 There are indications of other, still incompletely resolved transformations,3 closer to , or within, the SC region of the phase diagram. The interplay between superconductivity, magnetism and structure in doped La2CuO4 is the focus of continuing investigations.
KeywordsVortex Anisotropy Coherence
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- 5.Our model has many elements in common with earlier spin-hole models for the pairing of charges via magnetic interactions. See, for example, A. Aharony et al, Phys. Rev. Lett. 60, 1330 (1988)., and references therein.Google Scholar