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arXiv 1806.03066cond-mat.mtrl-sci
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LaAlO3/SrVO3异质结构的界面化学和电子性质

Interface chemical and electronic properties of LaAlO3/SrVO3 heterostructures

Arnaud Fouchet, Julien E. Rault, Mickaël Allain, Bruno Bérini, J. -P. Rueff, Yves Dumont, Niels Keller

摘要:

本文采用硬X射线光电子能谱和输运测量相结合的方法研究了LaAlO_3/SrVO_3复合薄膜的化学和电子性质。我们比较单一的SrVO 3(SVO)SrTiO 3薄膜和SrVO 3埋在下面的极性LaAlO 3(LAO)薄层,都外延生长在SrTiO 3。虽然SVO的SiO2膜(4个晶胞)在整个温度范围内确实显示出绝缘行为,但LAO/SVO界面在250 K处具有最小电阻率。当增加SVO层厚度时,观察到最小值向更高温度偏移,但电阻率始终保持小于可比SVO单层膜的电阻率。硬X射线光电子能谱揭示了表面或界面相关的V5+组件中的V 2 p光谱SVO膜和LAO/SVO异质结构,分别归因于一个强烈的氧化成分。这种化学重建是较弱的LAO/SVO异质结构相比,单SVO膜。我们发现,这种死层在SVO薄膜的薄膜厚度达到几个单元电池的限制时,必须考虑,并提出解决方案,如何防止这种不利的影响。

英文摘要:

We have studied the chemical and electronic properties of LaAlO3/SrVO3 ultrathin films by combining hard x-ray photoemission spectroscopy and transport measurements. We compare single SrVO3 (SVO) ultrathin films and SrVO3 buried below a polar LaAlO3 (LAO) thin layer, both epitaxially grown on SrTiO3. While ultrathin films (4 unit cells) of SVO do show insulating behavior over the entire temperature range, the LAO/SVO interface has a resistivity minimum at 250 K. When increasing the SVO layer thickness, the minimum is observed to shift to higher temperatures, but the resistivity stays always smaller than that of comparable SVO single films. Hard x-ray photoemission spectroscopy reveals a surface or interface related V5+ component in the V 2p spectra for SVO films and LAO/SVO heterostructures, respectively, attributed to a strongly oxidized component. This chemical reconstruction is weaker in LAO/SVO heterostructures compared to single SVO films. We show that this dead layer in SVO ultrathin films has to be considered when the film thickness reaches the few unit-cells limit and propose solutions on how to prevent this detrimental effect.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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