Electric field control of the LaAlO3/SrTiO3 interface ground state
Electric field control of the LaAlO3/SrTiO3 interface ground state
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DOI：
10.1038/nature07576
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发表时间：
2008-12-04
期刊：
影响因子：
64.8
通讯作者：
Triscone, J. -M.
中科院分区：
文献类型：
--
作者：
Caviglia, A. D.;Gariglio, S.;Triscone, J. -M.
复合氧化物之间的界面是凝聚态物理中最有趣的系统之一(1)。在这种特殊的环境中，平移对称被人为地打破，各种新的和不寻常的电子相可以被促进(2)。理论研究预测了复杂的相图，并提出了载流子密度在决定系统基态中的关键作用。一个特别吸引人的系统是带绝缘体LaAlO3和SrTiO3之间的导电界面（参考文献3）。最近，两种可能的基态已被实验确定：磁性态(4)和二维超导凝聚态(5)。这里我们利用电场效应来探讨系统的相图。载流子密度的静电调谐允许超导性的开/关开关，并驱动二维超导态和绝缘态之间的量子相变（6-8）。绝缘状态下的磁输运性质分析与弱局域化一致，不能提供磁性的证据。本文所证明的超导电场控制为新型介观超导电路的发展开辟了道路。
Interfaces between complex oxides are emerging as one of the most interesting systems in condensed matter physics(1). In this special setting, in which translational symmetry is artificially broken, a variety of new and unusual electronic phases can be promoted(2). Theoretical studies predict complex phase diagrams and suggest the key role of the charge carrier density in determining the systems' ground states. A particularly fascinating system is the conducting interface between the band insulators LaAlO3 and SrTiO3 ( ref. 3). Recently two possible ground states have been experimentally identified: a magnetic state(4) and a two- dimensional superconducting condensate(5). Here we use the electric field effect to explore the phase diagramof the system. The electrostatic tuning of the carrier density allows an on/off switching of superconductivity and drives a quantum phase transition(6-8) between a two- dimensional superconducting state and an insulating state. Analyses of the magnetotransport properties in the insulating state are consistent with weak localization and do not provide evidence for magnetism. The electric field control of superconductivity demonstrated here opens the way to the development of new mesoscopic superconducting circuits.