Electro-Mechanical Response of Top-Gated LaAlO3/SrTiO3 Heterostructures
Electro-Mechanical Response of Top-Gated LaAlO3/SrTiO3 Heterostructures
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顶栅 LaAlO3/SrTiO3 异质结构的机电响应
DOI：
10.1063/1.4940045
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
J. Levy
中科院分区：
文献类型：
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作者：
Feng Bi;Mengchen Huang;C. Bark;S. Ryu;Sanghan Lee;C. Eom;P. Irvin;J. Levy
LaAlO_3/SrTiO_3异质结在耗尽附近表现出急剧的、滞后的金属-绝缘体转变(MIT)，具有很大的电容增强效应。为了理解这一行为的物理根源，我们利用压电力显微镜(PFM)和电容谱两种同时测量技术研究了顶栅LaAlO_3/SrTiO_3异质结的机电响应。PFM测量揭示了滞后响应的局部变化，这与电容测量直接相关。麻省理工学院的电容增强与纳米级导电岛的充放电动力学有关，这通过PFM成像以及时间分辨电容和压电响应测量揭示了这一点。
LaAlO3/SrTiO3 heterostructures are known to exhibit a sharp, hysteretic metal-insulator transition (MIT) with large enhanced capacitance near depletion. To understand the physical origin of this behavior, the electromechanical response of top-gated LaAlO3/SrTiO3 heterostructures is probed using two simultaneous measurement techniques: piezoforce microscopy (PFM) and capacitance spectroscopy. PFM measurements reveal local variations in the hysteretic response, which is directly correlated with capacitance measurements. The enhanced capacitance at the MIT is linked to charging/discharging dynamics of nanoscale conducting islands, which are revealed through PFM imaging and time-resolved capacitance and piezoresponse measurements.