Ferromagnetic MnAs grown on GaAs(001): In situ investigations
Ferromagnetic MnAs grown on GaAs(001): In situ investigations
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GaAs(001) 上生长的铁磁 MnAs：原位研究
DOI：
10.1116/1.1305284
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发表时间：
2000
影响因子：
1.4
通讯作者：
K. Ploog
中科院分区：
文献类型：
--
作者：
M. Kästner;F. Schippan;P. Schützendübe;L. Däweritz;K. Ploog
用分子束外延法在GaAs（001）衬底上生长了α-MnAs铁磁层。生长过程中的表面进行了研究，通过反射高能电子衍射（RHEED）和反射差光谱（RDS）和生长后的原位扫描隧道显微镜（STM）。在c（4×4）重构的GaAs（001）表面上成核时，RHEED图消失。在这个阶段的STM图像显示明确的步骤和平坦的梯田，但在梯田上的无序结构。沉积后的1.5 ML的MnAs小的三维集群已被观察到STM。对于较厚的层的几个相的MnAs（1100）表面具有不同的重建已被观察到的RHEED。在265 °C衬底温度和0.2-0.65 ML/s的沉积速率下，已发现富As生长的镜面斑点的强度振荡。 对于低于360 °C的温度，在RD光谱中发现对表面重构敏感的特征。 在较高的温度下，RD谱并不消失。
We have grown ferromagnetic α-MnAs layers on GaAs(001) by molecular beam epitaxy. The surface was studied during growth by reflection high-energy electron diffraction (RHEED) and reflectance difference spectroscopy (RDS) and after growth by in situ scanning tunneling microscopy (STM). During nucleation on the c(4×4) reconstructed GaAs(001) surface the RHEED pattern disappears. STM images at this stage show well defined steps and flat terraces, but a disordered structure on the terraces. After deposition of 1.5 ML MnAs small three-dimensional clusters have been observed by STM. For thicker layers several phases of the MnAs(1100) surface with different reconstructions have been observed by RHEED. Intensity oscillations of the specular spot have been found for As-rich growth at 265 °C substrate temperature and deposition rates of 0.2–0.65 ML/s. For temperatures below 360 °C a feature was found in the RD spectra that is sensitive to the surface reconstruction. At higher temperatures the RD spectra did not de...