Semi-epitaxial SmB6 thin Films prepared by the molecular beam epitaxy
Semi-epitaxial SmB6 thin Films prepared by the molecular beam epitaxy
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分子束外延法制备半外延SmB6薄膜
DOI：
10.1016/j.phpro.2015.12.049
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
T. Ishida
中科院分区：
文献类型：
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作者：
H. Shishido;Y. Yoneda;T. Yoshida;S. Noguchi;T. Ishida
我们用分子束外延在高于1×10−6 Pa的超高真空下生长SmB 6薄膜。在MgO（100）衬底上，采用Knudsen池蒸发Sm和B，B和Sm的沉积速率比B/Sm在4.0 ~ 5.7之间，衬底温度为1000 ℃。反射高能电子衍射图显示斑点状的，表明相对平坦的膜表面。这与原子力显微镜测量的表面粗糙度是一致的。面间和面内X射线衍射结果表明，当B/Sm = 4.0时，SmB 4薄膜择优生长。我们获得了B/Sm比在4.9和5.7之间的SmB 6薄膜。X射线衍射测量澄清，我们的SmB 6薄膜显示部分外延生长的证据，作为主要领域的取向沿着[100] SmB 6 [100]MgO。面内取向的结晶度随着接近B/Sm = 6的化学计量沉积速率而改善。作为半导体，电阻率随着温度的降低而增加，并且在低温下变得恒定。这些特征很好地再现了所观察到的整体样品电阻率的趋势。
We grow thin films of SmB6 by molecular beam epitaxy under ultra-high vacuum better than 1×10−6 Pa. Sm and B were evaporated independently by Knudsen cells with the deposition rate ratio of B and Sm as B/Sm in between 4.0 and 5.7 on an MgO (100) substrate with the substrate temperature of 1000∘C. Reflection high energy electron diffraction patterns show spotted ones indicating a relatively flat film surfaces. This is in good agreement with the surface roughness measured by the atomic force microscope. Interplane and inplane X-ray diffraction measurements represent the preference growth ofc-axis oriented SmB4 thin films with the ratio B/Sm = 4.0. We obtained SmB6 thin films with the ratio B/Sm in between 4.9 and 5.7. X-ray diffraction measurements clarify that our SmB6 thin films show evidence of partial epitaxial growth as major domains orienting along [100]SmB6 ∥ [100]MgO. Crystallinity of inplane alignment is improved with approaching the stoichiometric deposition rate of B/Sm = 6. The electrical resistivity increases with decreasing temperature as a semiconductor, and becomes constant at low temperatures. These features well reproduce the tendency observed for the resistivity of bulk samples.