A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface
A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface
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DOI：
10.1038/nature02308
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发表时间：
2004-01-29
期刊：
影响因子：
64.8
通讯作者：
Hwang, HY
中科院分区：
文献类型：
--
作者：
Ohtomo, A;Hwang, HY
由于存在悬挂键和不完整的原子配位，不同晶体材料之间界面（异质界面）的极性不连续性可能导致非平凡的局部原子和电子结构（1-3）。这些不连续性通常出现在天然层状氧化物结构中，例如超导铜氧化物和铁电钛酸盐，以及人造薄膜氧化物异质结构中，例如锰氧化物隧道结（4-6）。如果极性不连续性可以原子控制，不寻常的电荷状态，是无法在散装材料可以实现。在这里，我们已经研究了两个绝缘钙钛矿氧化物-LaAlO 3和SrTiO 3-之间的模型界面，其中我们在原子尺度上控制界面处的终止层。在简单的离子极限下，这个界面在每个二维晶胞中呈现出额外的半个电子或空穴，这取决于界面的结构。空穴掺杂的界面是绝缘的，而电子掺杂的界面是导电的，具有极高的载流子迁移率超过10，000 cm（2）V-1 s（-1）。在低温下，观察到与反向磁场周期性的剧烈的磁阻振荡，表明量子输运。这些结果提出了一个广阔的机会，定制低维电荷状态的原子工程氧化物异质外延。
Polarity discontinuities at the interfaces between different crystalline materials (heterointerfaces) can lead to nontrivial local atomic and electronic structure, owing to the presence of dangling bonds and incomplete atomic coordinations(1-3). These discontinuities often arise in naturally layered oxide structures, such as the superconducting copper oxides and ferroelectric titanates, as well as in artificial thin film oxide heterostructures such as manganite tunnel junctions(4-6). If polarity discontinuities can be atomically controlled, unusual charge states that are inaccessible in bulk materials could be realized. Here we have examined a model interface between two insulating perovskite oxides - LaAlO3 and SrTiO3 - in which we control the termination layer at the interface on an atomic scale. In the simple ionic limit, this interface presents an extra half electron or hole per two-dimensional unit cell, depending on the structure of the interface. The hole-doped interface is found to be insulating, whereas the electron-doped interface is conducting, with extremely high carrier mobility exceeding 10,000 cm(2) V-1 s(-1). At low temperature, dramatic magnetoresistance oscillations periodic with the inverse magnetic field are observed, indicating quantum transport. These results present a broad opportunity to tailor low-dimensional charge states by atomically engineered oxide heteroepitaxy.