Evidence of linear lattice expansion and covalency enhancement in rutile TiO2 nanocrystals

被引：189

作者：

Li, GS

Boerio-Goates, J

Woodfield, BF ^{[1
]}

Li, LP

机构：

[1] Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA

[2] Brigham Young Univ, Dept Phys, Provo, UT 84602 USA

来源：

APPLIED PHYSICS LETTERS | 2004年 / 85卷 / 11期

关键词：

This work was supported with a grant (DE-FG03-01ER15235) from the U.S. Department of Energy. The authors wish to thank Professor Alexandra Navrotsky; University of California at Davis; and Professor Frances Hellman; University of California at Berkeley; for many fruitful discussions as part of our on-going collaboration;

D O I：

10.1063/1.1790596

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

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 [Phys. Rev. Lett. 2000, 85, 3440] and V. R. Palkar [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 Ti-O bond lengths in the expanded lattice. (C) 2004 American Institute of Physics.

引用

页码：2059 / 2061

页数：3

共 26 条

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