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

Mannella, N. ; Yang, W. L. ; Tanaka, K. ; Zhou, X. J. ; Zheng, H. ; Mitchell, J. F. ; Zaanen, J. ; Devereaux, T. P. ; Nagaosa, N. ; Hussain, Z. ; Shen, Z. -X.

Stanford Linear Accelerator Center

关键词: Exchange Interactions;    Magnetoresistance;    General Physics,Phys;    Polarons;    Curie Point;   

DOI  :  10.2172/920014
RP-ID  :  SLAC-PUB-13017
RP-ID  :  AC02-76SF00515
RP-ID  :  920014

美国|英语

来源: UNT Digital Library

【 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.