氦原子散射研究得到的掺铌钾钽酸钾 KTa(1-x)Nb(x)O3 的表面结构。

Surface structure of niobium-doped potassium tantalate KTa(1-x)Nb(x)O3 obtained from helium atom scattering studies.

机构信息

MARTECH and Department of Physics, Florida State University, Tallahassee, FL 32306-4350, USA.

出版信息

J Phys Condens Matter. 2010 Aug 4;22(30):304009. doi: 10.1088/0953-8984/22/30/304009. Epub 2010 Jul 13.

Abstract

Helium atom scattering experiments have been carried out on the (001) surface of KTaO(3) doped with 6, 10 and 15% Nb, produced by cleaving in situ single crystal samples. Several phenomena were observed through He atom diffraction measurements, including metastable behavior immediately after cleaving, reconstruction of a fraction of the surface to (2 × 1) domains after thermally cycling the surface temperatures, and the distribution of step heights of terraces at the surface as multiples of the unit cell dimension of ∼ 4 Å. In addition, a large hysteresis effect was found in the (100) azimuth in the variation of surface reflectivity with surface temperature; a much smaller hysteresis effect was found in the (110) azimuth. The hysteresis effects appear for all Nb doping concentrations. Finally, small oscillations in the specular and Bragg diffraction intensities near the surface temperature 80 K were also observed.

摘要

氦原子散射实验已在（001）面上进行，该表面是由原位单晶样品劈裂而成的掺杂了 6%、10%和 15%铌的 KTaO(3)。通过氦原子衍射测量观察到了几种现象，包括劈裂后立即出现的亚稳态行为、在表面温度热循环后部分表面重构为（2×1）畴，以及表面台阶高度分布作为约 4 Å 的单元晶格尺寸的倍数。此外，在（100）方位角中，表面反射率随表面温度的变化存在较大的滞后效应；在（110）方位角中发现了较小的滞后效应。滞后效应出现在所有铌掺杂浓度下。最后，在接近 80 K 的表面温度附近，镜面和布拉格衍射强度也出现了小的振荡。