Electrostatic fields tune the ground state of interfaces between complex oxide materials. Electronic properties, such as conductivity and superconductivity, can be tuned and then used to create and control circuit elements and gate-defined devices. Here we show that naturally occurring twin boundaries, with properties that are different from their surrounding bulk, can tune the LaAlO₃/SrTiO₃ interface 2DEG at the nanoscale. In particular, SrTiO₃ domain boundaries have the unusual distinction of remaining highly mobile down to low temperatures, and were recently suggested to be polar. Here we apply localized pressure to an individual SrTiO₃ twin boundary and detect a change in LaAlO₃/SrTiO₃ interface current distribution. Our data directly confirm the existence of polarity at the twin boundaries, and demonstrate that they can serve as effective tunable gates. As the location of SrTiO₃ domain walls can be controlled using external field stimuli, our findings suggest a novel approach to manipulate SrTiO₃-based devices on the nanoscale.

静电场可调节复杂氧化物材料之间界面的基态。可以调整电导率和超导率等电子属性，然后将其用于创建和控制电路元件以及门限器件。在这里，我们显示了自然界中存在的孪晶边界，其性质与其周围的体积不同，它们可以在纳米尺度上调节LaAlO ₃ / SrTiO ₃界面2DEG。特别地，SrTiO ₃畴边界具有在低温下仍保持高度移动性的非同寻常的区别，并且最近被认为是极性的。在这里，我们对单个SrTiO ₃双晶边界施加局部压力，并检测LaAlO ₃ / SrTiO _3的变化接口电流分布。我们的数据直接证实了孪生边界处极性的存在，并证明它们可以用作有效的可调门。由于可以使用外部场刺激来控制SrTiO ₃畴壁的位置，因此我们的发现提出了一种在纳米级上操纵基于SrTiO ₃的器件的新颖方法。