Theory of the broadening of vibrational spectra induced by lowered symmetry in yttria nanostructures

H. Bao, X. L. Ruan, and M. Kaviany

Phys. Rev. B 78, 125417 – Published 23 September 2008

Abstract

We calculate the vibrational spectra for typical nanostructures including thin films, nanowires, and quantum dots of yttria, an important laser host material. Lattice dynamics calculations show that the vibrational spectra of nanocrystals are distinct from that of the bulk phase in the enhanced tails at low and high frequencies. Some of the low-frequency and high-frequency modes only involve surface atoms. Molecular-dynamics simulations are used to further decompose the contributions of surface and internal atoms, and the results confirm the evident broadening of the surface spectra. The broadening in vibrational spectra is attributed to the broadened atomic spring constants, further to the lowered symmetry of nanostructures.

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Received 16 May 2008

DOI:https://doi.org/10.1103/PhysRevB.78.125417

Authors & Affiliations

H. Bao¹, X. L. Ruan^1,2,*, and M. Kaviany³

¹School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
²Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
³Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA

^*Author to whom correspondence should be addressed. ruan@purdue.edu

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Issue

Vol. 78, Iss. 12 — 15 September 2008

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