Size-dependent vibronic coupling in α-Fe2O3

K R O'Neal; J M Patete; P Chen; B S Holinsworth; J M Smith; N Lee; S-W Cheong; Stanislaus S Wong; C Marques; M C Aronson; J L Musfeldt

doi:10.1063/1.4887359

Size-dependent vibronic coupling in α-Fe2O3

J Chem Phys. 2014 Jul 28;141(4):044710. doi: 10.1063/1.4887359.

Authors

K R O'Neal¹, J M Patete², P Chen¹, B S Holinsworth¹, J M Smith², N Lee³, S-W Cheong⁴, Stanislaus S Wong², C Marques⁵, M C Aronson⁶, J L Musfeldt¹

Affiliations

¹ Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, USA.
² Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400, USA.
³ Department of Physics and IPAP, Yonsei University, Seoul 120-749, South Korea.
⁴ Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA.
⁵ Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA.
⁶ Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.

PMID: 25084940
DOI: 10.1063/1.4887359

Abstract

We report the discovery of finite length scale effects on vibronic coupling in nanoscale α-Fe2O3 as measured by the behavior of vibronically activated d-d on-site excitations of Fe(3+) as a function of size and shape. An oscillator strength analysis reveals that the frequency of the coupled symmetry-breaking phonon changes with size, a crossover that we analyze in terms of increasing three-dimensional character to the displacement pattern. These findings demonstrate the flexibility of mixing processes in confined systems and suggest a strategy for both enhancing and controlling charge-lattice interactions in other materials.