权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Fabrication of two-dimensional electron gas with high mobility in SrTiO_3 to develop novel quantum

在SrTiO_3中制备高迁移率二维电子气以开发新型量子

基本信息

批准号：
17340103
负责人：
HWANG H.Y
金额：
$ 10.05万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17340103/
关键词：
Strongly correlated electron system Crystal growth Low-temperature physics Low-dimensional physics

项目摘要

This project is aimed at realizing a two-dimensional electron gas in SrTiO_3. For that purpose, it is essential to fabricate heterostructures and to understand electronic structures at the heterointerfaces. We report our results related to this purpose.1. We have deposited LaAlO_3 films on SrTiO_3(100) substrates and probed the interface electronic structure by EELS. For SrO-terminated substrates, holes generated by the polar discontinuity were compensated by oxygen vacancies. This is the result of the removal of the band offset, which was also observed for an n-type interface originating from TiO_2-terminated substrates.2. We have probed the interface electronic structure at an interface of strontium titanate and transition-metal oxides by measuring junction properties. As a result, we have found a chemical potential shift by magnetic field at the interface of manganite, which modulates the junction properties. Precise analysis has revealed the importance of electron tunneling in the junction properties.3. We have observed the Schottky barrier height formed at SrRuO_3/Nb : SrTiO_3 interface by internal photoemission spectroscopy. As a result, the interface can be described by the Schottky-Mott model. We have found that this method can be generally applicable to other interfaces composed of transition-metal oxides.4. We have fabricated a quantum well structure by a Mott insulator and probed the electronic states. We have used lanthanum vanadate. As a result, we have found the existence of tetravalent vanadium, which does not exist in a bulk form, at the top layer of the vanadate due to a charge reconstruction by x-ray photoemission spectroscopy. In addition, a competing phase of trivalent vanadium and pentavalent vanadium is formed by adjusting growth conditions. We have also found tetravalent vanadium at the phase boundary by EELS.

本项目的目标是在SrTiO_3中实现二维电子气。为此，制造异质结构和理解异质界面处的电子结构是必不可少的。我们报告我们的结果与此相关的目的。1.我们在SrTiO_3（100）衬底上沉积了LaAlO_3薄膜，并用EELS研究了LaAlO_3薄膜的界面电子结构。对于SrO终止的衬底，由极性不连续产生的空穴由氧空位补偿。这是由于带偏移的消除，这也被观察到的n型界面源于TiO_2终止基板.通过测量钛酸锶与过渡金属氧化物的结特性，研究了钛酸锶与过渡金属氧化物的界面电子结构。结果发现，在锰氧化物界面处，磁场引起化学势移动，从而调制结的性质。精确的分析揭示了电子隧穿在结特性中的重要性.我们用内光电子能谱观察到SrRuO_3/Nb：SrTiO_3界面上形成的肖特基势垒高度。因此，界面可以用Schottky-Mott模型来描述。我们发现这种方法可以普遍适用于其他过渡金属氧化物组成的界面.我们用Mott绝缘体制作了量子阱结构，并对其电子态进行了探测。我们使用钒酸镧。其结果是，我们已经发现存在的四价钒，这并不存在于散装形式，在钒酸盐的顶层由于电荷重建的X-射线光电子能谱。此外，通过调节生长条件，形成了三价钒和五价钒的竞争相。我们还发现了四价钒在相界的EELS。