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arXiv 1708.09189cond-mat.mtrl-sci
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通过金属覆盖层的原位沉积调节LaAlO3/SrTiO3中的临界厚度

Tuning up or down the critical thickness in LaAlO3/SrTiO3 through in situ deposition of metal overlayers

D. C. Vaz, E. Lesne, H. Naganuma, E. Jacquet, J. Santamaria, A. Barthelemy, M. Bibes

摘要:

在LaAlO 3和SrTiO 3之间的界面处形成的准二维电子系统(q2 DES)引起了氧化物电子学界的广泛关注。其标志性特征之一是存在临界LaAlO 3厚度为4个晶胞(uc)的界面电导率出现。在本文中,化学,电子和输运性质的LaAlO 3/SrTiO 3样品覆盖不同的金属生长在一个系统相结合的脉冲激光沉积,溅射,原位X射线光电子能谱的研究。结果表明,对于具有低功函数的金属,在LaAlO 3的1-2 μ c处形成q2 DES,并且伴随着金属的部分氧化,这一现象影响q2 DES的性质并触发缺陷的形成。相反,对于贵金属,临界厚度增加到4 μ c以上。结果进行了讨论的混合机制,结合静电和化学效应。

英文摘要:

The quasi 2D electron system (q2DES) that forms at the interface between LaAlO3 and SrTiO3 has attracted much attention from the oxide electronics community. One of its hallmark features is the existence of a critical LaAlO3 thickness of 4 unit-cells (uc) for interfacial conductivity to emerge. In this paper, the chemical, electronic, and transport properties of LaAlO3/SrTiO3 samples capped with different metals grown in a system combining pulsed laser deposition, sputtering, and in situ X-ray photoemission spectroscopy are investigated. The results show that for metals with low work function a q2DES forms at 1-2 uc of LaAlO3 and is accompanied by a partial oxidation of the metal, a phenomenon that affects the q2DES properties and triggers the formation of defects. In contrast, for noble metals, the critical thickness is increased above 4 uc. The results are discussed in terms of a hybrid mechanism that incorporates electrostatic and chemical effects.

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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