Local switching of two-dimensional superconductivity using the ferroelectric field effect
Local switching of two-dimensional superconductivity using the ferroelectric field effect
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DOI：
10.1038/nature04731
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发表时间：
2006-05-11
期刊：
影响因子：
64.8
通讯作者：
Triscone, JM
中科院分区：
文献类型：
--
作者：
Takahashi, KS;Gabay, M;Triscone, JM
相关氧化物显示出各种非凡的物理性质，包括高温超导性（1）和巨磁阻（2）。在这些材料中，强的电子相关性通常导致竞争基态，这些基态对许多参数敏感-特别是掺杂水平，从而观察到复杂的相图。探索掺杂作用的一种灵活方法是用电场调节电子或空穴浓度，就像标准半导体场效应晶体管中所做的那样（3）。在这里，我们展示了一个模型氧化物系统的基础上，高品质的异质结构中的铁电场效应的方法可以进行研究。我们使用铌掺杂的钙钛矿超导体SrTiO_3的单晶薄膜作为超导沟道和铁电体Pb（Zr，Ti）O_3作为栅氧化物。原子力显微镜被用来局部反转铁电极化，从而诱导大的电阻率和载流子调制，导致在超导临界温度的一个明确的转变。场致开关从正常状态（零电阻）超导状态实现在一个明确定义的温度。这种独特的系统可能会导致一个研究领域，其中设备是通过在同一材料中局部定义超导和正常区域实现的“完美”界面，界面是纯电子的。使用这种方法，人们可以设计一维超导导线，超导环和结，超导量子干涉器件（SQUID）或钉扎中心阵列。
Correlated oxides display a variety of extraordinary physical properties including high-temperature superconductivity(1) and colossal magnetoresistance(2). In these materials, strong electronic correlations often lead to competing ground states that are sensitive to many parameters - in particular the doping level so that complex phase diagrams are observed. A flexible way to explore the role of doping is to tune the electron or hole concentration with electric fields, as is done in standard semiconductor field effect transistors(3). Here we demonstrate a model oxide system based on high-quality heterostructures in which the ferroelectric field effect approach can be studied. We use a single-crystal film of the perovskite superconductor Nb-doped SrTiO3 as the superconducting channel and ferroelectric Pb(Zr, Ti) O-3 as the gate oxide. Atomic force microscopy is used to locally reverse the ferroelectric polarization, thus inducing large resistivity and carrier modulations, resulting in a clear shift in the superconducting critical temperature. Field-induced switching from the normal state to the ( zero resistance) superconducting state was achieved at a well-defined temperature. This unique system could lead to a field of research in which devices are realized by locally defining in the same material superconducting and normal regions with `perfect' interfaces, the interface being purely electronic. Using this approach, one could potentially design one-dimensional superconducting wires, superconducting rings and junctions, superconducting quantum interference devices ( SQUIDs) or arrays of pinning centres.