Kwak Yongsu, Han Woojoo, Lee Joon Sung, Song Jonghyun, Kim Jinhee
Korea Research Institute of Standards and Science, Daejeon, 34113, South Korea.
Department of Physics, Chungnam National University, Daejeon, 34134, South Korea.
Sci Rep. 2022 Apr 19;12(1):6458. doi: 10.1038/s41598-022-10425-3.
For two-dimensional electron gas device applications, it is important to understand how electrical-transport properties are controlled by gate voltage. Here, we report gate voltage-controllable hysteresis in the resistance-temperature characteristics of two-dimensional electron gas at LaAlO/SrTiO heterointerface. Electron channels made of the LaAlO/SrTiO heterointerface showed hysteretic resistance-temperature behavior: the measured resistance was significantly higher during upward temperature sweeps in thermal cycling tests. Such hysteretic behavior was observed only after application of positive back-gate voltages below 50 K in the thermal cycle, and the magnitude of hysteresis increased with the applied back-gate voltage. To explain this gate-controlled resistance hysteresis, we propose a mechanism based on electron trapping at impurity sites, in conjunction with the strong temperature-dependent dielectric constant of the SrTiO substrate. Our model explains well the observed gate-controlled hysteresis of the resistance-temperature characteristics, and the mechanism should be also applicable to other SrTiO-based oxide systems, paving the way to applications of oxide heterostructures to electronic devices.
对于二维电子气器件应用而言，了解电输运特性如何受栅极电压控制至关重要。在此，我们报道了在LaAlO₃/SrTiO₃异质界面处二维电子气的电阻 - 温度特性中存在栅极电压可控的滞后现象。由LaAlO₃/SrTiO₃异质界面构成的电子通道呈现出滞后的电阻 - 温度行为：在热循环测试中，向上温度扫描期间测得的电阻显著更高。这种滞后行为仅在热循环中施加低于50 K的正背栅电压后才观察到，并且滞后幅度随所施加的背栅电压增加。为了解释这种栅极控制的电阻滞后现象，我们提出了一种基于杂质位点处电子俘获并结合SrTiO₃衬底强烈温度依赖性介电常数的机制。我们的模型很好地解释了所观察到的电阻 - 温度特性的栅极控制滞后现象，并且该机制也应适用于其他基于SrTiO₃的氧化物体系，为氧化物异质结构在电子器件中的应用铺平了道路。
