Elasticity-driven nanoscale texturing in complex electronic materials
Theoretical Division, Los Alamos National
Laboratory - Los Alamos, NM 87544, USA
2 International Centre for Theoretical Physics - 34014 Trieste, Italy
Accepted: 20 May 2003
Fine-scale probes of many complex electronic materials have revealed a non-uniform nanoworld of sign-varying textures in strain, charge and magnetization, forming meandering ribbons, stripe segments or droplets. We introduce and simulate a Ginzburg-Landau model for a structural transition, with strains coupling to charge and magnetization. Charge doping acts as a local stress that deforms surrounding unit cells without generating defects. This seemingly innocuous constraint of elastic “compatibility” in fact induces crucial anisotropic long-range forces of unit cell discrete symmetry, that interweave opposite-sign competing strains to produce polaronic elasto-magnetic textures in the composite variables. Simulations with random local doping below the solid-solid transformation temperature reveal rich multiscale texturing from induced elastic fields: nanoscale phase separation, mesoscale intrinsic inhomogeneities, textural cross-coupling to external stress and magnetic field, and temperature-dependent percolation. We describe how this composite textured polaron concept can be valuable for doped manganites, cuprates and other complex electronic materials.
PACS: 71.38.-k – Polarons and electron-phonon interactions / 75.47.Gk – Colossal magnetoresistance / 74.72.-h – Cuprate superconductors (high-Tc and insulating parent compounds)
© EDP Sciences, 2003