Direct observation of substitutional Au atoms in SrTiO3

C. M. Wang, V. Shutthanandan, Y. Zhang, S. Thevuthasan, G. Duscher

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Abstract

Ion implantation and subsequent high-temperature annealing is an effective way to prepare metal nanoclusters dispersed in a dielectric for useful optical and electrical properties. However, there is very little understanding of the nucleation and growth process of these nanoclusters, their correlations with the sites of the implanted ions, and the behavior of defects (such as vacancies) generated during the ion-implantation process. Using high-angle annular dark-field imaging in aberration-corrected scanning transmission electron microscopy, we have directly observed that, at a dilute concentration, Au atoms implanted in SrTiO3 are in a substitutional lattice position for both Sr and Ti. The congregation of Au atoms by diffusion to a critical concentration leads to the nucleation of an Au lattice within the SrTiO 3. The Au nanocluster and SrTiO3 were found to maintain an orientation relationship of Au[001]//SrTiO3[001] and Au(100)//SrTiO3(100), which corroborated the results of a first-principles total-energy calculation. The interface between the Au cluster and SrTiO3 was bridged by an O/Ti plane. The Au-O bond length was found to be 2.2 Å, which is the same as the Au-O bond length in AuO. Furthermore, the atomic planes adjacent to the interface in both Au and SrTiO3 were found to be slightly stretched. The high concentration of vacancies generated during the Au implantation aggregated to form cavities in the SrTiO3 lattice, and were faceted mostly along the SrTiO 3 {100} and (110) planes. The Au and vacancy clusters were spatially associated, indicating a strong interaction. Thus, the formation of cavities in Au-implanted materials indicates that the vacancy-clustering process prevails over the Frenkel-pair recombination.

Original languageEnglish
Article number172201
Pages (from-to)1-4
Number of pages4
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume70
Issue number17
DOIs
Publication statusPublished - Nov 2004
Externally publishedYes

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ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Wang, C. M., Shutthanandan, V., Zhang, Y., Thevuthasan, S., & Duscher, G. (2004). Direct observation of substitutional Au atoms in SrTiO3. Physical Review B - Condensed Matter and Materials Physics, 70(17), 1-4. [172201]. https://doi.org/10.1103/PhysRevB.70.172201