论文标题
各向异性Rashba耦合到KTAO3中的极性模式
Anisotropic Rashba coupling to polar modes in KTaO3
论文作者
论文摘要
由于在基于KTAO3的异质结构中发现超导性的动机，我们研究了一种基于传导电子和材料中存在的铁电模式之间的自旋轨道辅助耦合的配对机制。我们使用从头静止的冷冻 - 波计算来显示线性弹药样耦合的线性耦合，并且在动量中具有很强的角度依赖性，对于较低的J = 3/2歧管，与常规的各向同性Rashba模型偏离。这意味着与极性模式的Rashba样相互作用具有实质性的L = 3立方谐波校正，我们为每个电子带进行了量化。 RASHBA相互作用的强各向异性是由T2G电子的微观玩具模型捕获的。我们发现它的起源是动力学项对退化j = 3/2歧管施加的电子动量的角度依赖性。玩具模型与从头算结果之间的比较表明，需要额外的对称性允许的术语超出奇数旋转旋转的轨道间跳跃过程，以描述电子与软铁电模式之间的Rashba样极性相互作用。
Motivated by the discovery of superconductivity in KTaO3-based heterostructures, we study a pairing mechanism based on spin-orbit assisted coupling between the conduction electrons and the ferroelectric modes present in the material. We use ab initio frozen-phonon computations to show a linear-in-momentum Rashba-like coupling with a strong angular dependence in momentum for the lower j=3/2 manifold, deviating from the conventional isotropic Rashba model. This implies the Rashba-like interaction with the polar modes has substantial L=3 cubic harmonic corrections, which we quantify for each electronic band. The strong anisotropy of the Rashba interaction is captured by a microscopic toy model for the t2g electrons. We find its origin to be the angular dependence in electronic momentum imposed by the kinetic term on the degenerate j=3/2 manifold. A comparison between the toy model and ab initio results indicate that additional symmetry allowed terms beyond odd-parity spin-conserving inter-orbital hopping processes are needed to describe the Rashba-like polar interaction between the electrons and the soft ferroelectric mode.
