Colossal flexoresistance in dielectrics
Colossal flexoresistance in dielectrics
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DOI：
10.1038/s41467-020-16207-7
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发表时间：
2020-05
影响因子：
16.6
通讯作者：
S. Park;Bo Wang;T. Paudel;Se Young Park;Saikat Das;Jeong Rae Kim;E. Ko;H. Lee;Nahee Park
中科院分区：
文献类型：
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作者：
S. Park;Bo Wang;T. Paudel;Se Young Park;Saikat Das;Jeong Rae Kim;E. Ko;H. Lee;Nahee Park
电介质长期以来被认为不适合用于纯电开关;在弱电场下，它们表现出极低的导电性，而在强电场下，它们遭受不可逆的损伤。在这里，我们表明，flexoelectricity使无损伤的暴露在强电场中，导致电气状态之间的可逆切换绝缘和导电。应用应变梯度与原子力显微镜尖端极化的原型介电SrTiO 3通过flexoelectricity，这反过来又产生非破坏性的，强的静电场的一个dielectric薄膜。当施加的应变梯度超过一定值时，SrTiO 3突然变得高度导电，产生至少约108倍的室温电阻率降低。我们解释这种现象，我们称之为巨大的flexoresistance，在应变梯度下的隧道电导的突然增加的基础上，SrTiO 3。我们的工作扩展了固体电控制的范围，并激发了对强机电场介电响应的进一步探索。
Dielectrics have long been considered as unsuitable for pure electrical switches; under weak electric fields, they show extremely low conductivity, whereas under strong fields, they suffer from irreversible damage. Here, we show that flexoelectricity enables damage-free exposure of dielectrics to strong electric fields, leading to reversible switching between electrical states—insulating and conducting. Applying strain gradients with an atomic force microscope tip polarizes an ultrathin film of an archetypal dielectric SrTiO3via flexoelectricity, which in turn generates non-destructive, strong electrostatic fields. When the applied strain gradient exceeds a certain value, SrTiO3suddenly becomes highly conductive, yielding at least around a 108-fold decrease in room-temperature resistivity. We explain this phenomenon, which we call the colossal flexoresistance, based on the abrupt increase in the tunneling conductance of ultrathin SrTiO3under strain gradients. Our work extends the scope of electrical control in solids, and inspires further exploration of dielectric responses to strong electromechanical fields.