{"paper":{"title":"Anomalous low-energy phonons in nearly tetragonal BiFeO3 thin films","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cond-mat.str-el","authors_text":"C.-H. Yang, C. S. Woo, D. Wulferding, J. H. Lee, K. Chu, K.-Y. Choi, P. Lemmens, S. H. Do","submitted_at":"2011-08-23T03:01:05Z","abstract_excerpt":"We present evidence for a concomitant structural and ferroelectric transformation around $T_S\\sim 360$ K in multiferroic BiFeO$_3$/LaAlO$_3$ thin films close to the tetragonal phase. Phonon excitations are investigated by using Raman scattering as a function of temperature. The low-energy phonon modes at 180-260 cm$^{-1}$ related to the FeO$_6$ octahedron tilting show anomalous behaviors upon cooling through $T_S$; (i) a large hardening amounting to 15 cm$^{-1}$, (ii) an increase of intensity by one order of magnitude, and (iii) an appearance of a dozen new modes. In contrast, the high-frequen"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1108.4484","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}