Polaron Coherence Condensation As the Mechanism for Colossal Magnetoresistance in Layered Manganites

[摘要] Angle-resolved photoemission spectroscopy data for the bilayer manganite La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} show that, upon lowering the temperature below the Curie point, a coherent polaronic metallic groundstate emerges very rapidly with well defined quasiparticles which track remarkably well the electrical conductivity, consistent with macroscopic transport properties. Our data suggest that the mechanism leading to the insulator-to-metal transition in La{sub 1.2}Sr{sub 1.8}Mn{sub 2}O{sub 7} can be regarded as a polaron coherence condensation process acting in concert with the Double Exchange interaction.

[发布日期] 2007-11-20

[学科分类] 物理（综合）

[关键词] CURIE POINT;ELECTRIC CONDUCTIVITY;EXCHANGE INTERACTIONS;MAGNETORESISTANCE;PHOTOEMISSION;POLARONS;SPECTROSCOPY;TRANSPORT General Physics;PHYS