Some oxide interfaces are known to exhibit unique properties such as a 2D electron gas, controlled by epitaxial strain and coherency between the two layers. Here, we study variation in the 2D electron density in the polar LaIn_1-xGa_xO₃/Ba_0.997La_0.003SnO₃ interface with changing x and LaIn_1-xGa_xO₃ layer thickness. We find that the 2D electron density decreases as the gallium alloying ratio increases and the interface conductance eventually disappears, which shows that an interface with polar discontinuity is not a sufficient condition for 2D electron gas formation. The interface conductance reaches its maximum value when the LaIn_1-xGa_xO₃ layer thickness is approximately 20 Å, beyond which conductance decreased to a constant value. Atomistic imaging reveals that dislocations start to form as the gallium ratio increases, forming away from the interface and then moving closer with increasing gallium alloying. The dislocations eventually destroy coherency in the case of LaGaO₃ and suppress the formation of a 2D electron gas.

已知一些氧化物界面表现出独特的特性，例如二维电子气，由两层之间的外延应变和相干性控制。在这里，我们研究了极性 LaIn _1-x Ga _x O ₃ /Ba _0.997 La _0.003 SnO ₃界面中二维电子密度随 x 和 LaIn _{1- x} Ga _x O ₃变化的变化层厚度。我们发现二维电子密度随着镓合金化率的增加而降低，界面电导最终消失，这表明具有极性不连续性的界面不是二维电子气形成的充分条件。当 LaIn _1-x Ga _x O ₃层厚度约为 20 Å 时，界面电导达到最大值，超过该值时，电导降至恒定值。原子成像显示，随着镓比例的增加，位错开始形成，远离界面形成，然后随着镓合金化的增加而靠近。在 LaGaO ₃的情况下，位错最终会破坏相干性并抑制 2D 电子气的形成。