外場によるミクロ構造の変化--変調X線回折法による測定

概要

論文の詳細を見る
Extremely small ionic displacement (10-4-10-5Å) and electron redistribution in crystals induced by externally applied electric field (50-80kVcm-1) were directly detected by using a modulation X-ray diffraction method, where the small changes in the dif-fracted intensities (10-3-10-4) were measured synchronously with the alternative electric field. For LiNbO3 and LiTaO3, the displacement of the bonding electrons of Nb-O and Ta-O bonds was found to be much larger than that of the constituent ions, which may be the origin of the electro-optic effect. The temperature factor was also found to vary with the external field. For GaAs, the effective charge of Ga was determined to be positive (larger than+le) from the observed displacement of ions, contrary to most of the results reported earlier. The displacement of bond charges was found to be much smaller than that expected from Phillips, dielectric theory. The present method was proved to be useful for the dynamical analysis of metal-semiconductor and metal-insulator-semiconductor interfaces by the detection of a high electric field in the interface regions.
日本結晶学会の論文