Keywords

lattice expansion, covalency enhancement, nanocrystals

Abstract

Lattice variations and bonding characteristics in rutile TiO2 nanocrystals were examined by x-ray diffraction and x-ray photoelectron spectroscopy. With a reduction in the physical dimensions, rutile TiO2 nanocrystals show a linear lattice expansion and an anomalous covalency enhancement in apparent contradiction to the ionicity increase in BaTiO3 and CuO nanocrystals as reported recently by S. Tsunekawa et al. [Phys. Rev. Lett. 2000, 85, 3440] and V. R. Palkar et al. [Phys. Rev. B 1996, 53, 2167]. A surface defect dipole model is proposed to explain these physical phenomena in terms of the strong interactions among the surface dipoles that produce an increased negative pressure. The covalency enhancement is interpreted according to the critical properties of the increased TiO bond lengths in the expanded lattice

Original Publication Citation

Li, Guangshe, Juliana B. Goates, Brian F. Woodfield, and Liping Li."Evidence of linear lattice expansion and covalency enhancement in rutile TiO[sub 2] nanocrystals." Applied Physics Letters 85 (24): 259-261.

Document Type

Peer-Reviewed Article

Publication Date

2004-09-13

Permanent URL

http://hdl.lib.byu.edu/1877/1283

Publisher

AIP

Language

English

College

Physical and Mathematical Sciences

Department

Chemistry and Biochemistry

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