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- Title
Bilayer manganites reveal polarons in the midst of a metallic breakdown.
- Authors
Massee, F.; de Jong, S.; Huang, Y.; Siu, W. K.; Santoso, I.; Mans, A.; Boothroyd, A. T.; Prabhakaran, D.; Follath, R.; Varykhalov, A.; Patthey, L.; Shi, M.; Goedkoop, J. B.; Golden, M. S.
- Abstract
The origin of colossal magnetoresistance (CMR) in manganese oxides is among the most challenging problems in condensed-matter physics today. The true nature of the low-temperature electronic phase of these materials is heavily debated. By combining photoemission and tunnelling data, we show that in the archetypal bilayer system La2?2xSr1+2xMn2O7, polaronic degrees of freedom win out across the CMR region of the phase diagram. This means that the generic ground state of bilayer manganites supports a vanishing coherent quasi-particle spectral weight at the Fermi level throughout k-space. The incoherence of the charge carriers, resulting from strong electron-lattice interactions and the accompanying orbital physics, offers a unifying explanation for the anomalous charge-carrier dynamics seen in transport, optics and electron spectroscopies. The stacking number N is the key factor for true metallic behaviour, as an intergrowth-driven breakdown of the polaronic domination to give a metal possessing a traditional Fermi surface is seen in this system.
- Subjects
MANGANITE; POLARONS; MAGNETORESISTANCE; PHOTOEMISSION; FERROMAGNETIC materials
- Publication
Nature Physics, 2011, Vol 7, Issue 12, p978
- ISSN
1745-2473
- Publication type
Article
- DOI
10.1038/nphys2089