Phase diagrams of voltage-gated oxide interfaces with strong Rashba coupling
Phase diagrams of voltage-gated oxide interfaces with strong Rashba coupling
复制标题
具有强 Rashba 耦合的电压门控氧化物界面的相图
DOI：
10.1103/physrevb.89.195448
复制
发表时间：
2013
影响因子：
3.7
通讯作者：
S. Caprara
中科院分区：
文献类型：
--
作者：
D. Bucheli;M. Grilli;F. Peronaci;G. Seibold;S. Caprara
我们提出了一种在氧化物异质结构界面处形成的二维电子气模型，其中包括与垂直于界面的电场成比例的 Rashba 自旋轨道耦合。考虑到将电子气限制在界面处的电场对电子密度的依赖性，我们报告了在零温度下自旋轨道耦合和电子能带结构参数的实际值会出现相分离不稳定性（以负压缩率表示）。我们将分析扩展到有限温度和存在面内磁场的情况下，从而获得显示相分离圆顶的两个相图。通过改变选通电势，相分离圆顶可以在零温度下收缩并消失到电荷动态波动的量子临界点。类似地，即使在零温度下，相分离也可能被平面磁场破坏，导致出现量子临界点线。
We propose a model for the two-dimensional electron gas formed at the interface of oxide heterostructures that includes a Rashba spin-orbit coupling proportional to an electric field oriented perpendicularly to the interface. Taking into account the electron density dependence of this electric field confining the electron gas at the interface, we report the occurrence of a phase separation instability (signaled by a negative compressibility) for realistic values of the spin-orbit coupling and of the electronic band-structure parameters at zero temperature. We extend the analysis to finite temperatures and in the presence of an in-plane magnetic field, thereby obtaining two phase diagrams that exhibit a phase separation dome. By varying the gating potential, the phase separation dome may shrink and vanish at zero temperature into a quantum critical point where the charge fluctuates dynamically. Similarly, the phase separation may be spoiled by a planar magnetic field even at zero temperature leading to a line of quantum critical points.