Abstract
In this paper, we present the first structural investigation of quartz using helium atom scattering (HAS). Studies were carried out on the α-quartz (0 0 0 1) surface (Z-cut). He-diffraction experiments reveal a complex hexagonal diffraction pattern. Prominent peaks are visible at positions corresponding to the periodicity of the bulk unit cell (4.90 ± 0.02 Å). In addition, weak (2 × 2) peaks and satellite peaks are observed. Two recent theoretical papers both propose a (1 × 1) reconstruction for α-quartz (0 0 0 1) with 120° symmetry for the surface unit cell: the so called dense structure. We propose a model where terraces with step heights of a multiple 1/3 of the unit cell height lead to domains rotated by ±60° relative to each other. This is supported by AFM images. The satellite peaks indicate an incommensurate super-lattice structure with a periodicity of the order of 57 Å, presumably related to strain relief mechanisms. The (2 × 2) peaks may stem from co-existing regions of a semi-dense structure, which is predicted to have a higher energy than the dense, (1 × 1) phase.
Original language | English |
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Pages (from-to) | 4407-4411 |
Number of pages | 5 |
Journal | Surface Science |
Volume | 601 |
Issue number | 18 |
DOIs | |
Publication status | Published - 15 Sept 2007 |
Keywords
- AFM
- Helium atom scattering
- Quartz surface structure
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Condensed Matter Physics
- Surfaces and Interfaces