Title: Minimal Ingredients for Orbital Texture Switches at Dirac Points in Strong Spin-Orbit Coupled Materials Show Chinese title

Title: 强自旋-轨道耦合材料中狄拉克点处轨道纹理开关的最小组分

Abstract: Recent angle resolved photoemission spectroscopy measurements on strong spin-orbit coupled materials have shown an in-plane orbital texture switch at their respective Dirac points, regardless of whether they are topological insulators or "trivial" Rashba materials. This feature has also been demonstrated in a few materials ($\text{Bi}_2\text{Se}_3$, $\text{Bi}_2\text{Te}_3$, and $\text{BiTeI}$) though DFT calculations. Here we present a minimal orbital-derived tight binding model to calculate the electron wave-function in a two-dimensional crystal lattice. We show that the orbital components of the wave-function demonstrate an orbital-texture switch in addition to the usual spin switch seen in spin polarized bands. This orbital texture switch is determined by the existence of three main properties: local or global inversion symmetry breaking, strong spin-orbit coupling, and non-local physics (the electrons are on a lattice). Using our model we demonstrate that the orbital texture switch is ubiquitous and to be expected in many real systems. The orbital hybridization of the bands is the key aspect for understanding the unique wave function properties of these materials, and this minimal model helps to establish the quantum perturbations that drive these hybridizations. Show Chinese abstract

Abstract: 最近的角分辨光电子能谱测量在强自旋轨道耦合材料中显示，在各自的狄拉克点，平面内轨道纹理发生切换，无论它们是拓扑绝缘体还是“平凡”的Rashba材料。 这一特性已在几种材料（$\text{Bi}_2\text{Se}_3$，$\text{Bi}_2\text{Te}_3$，和$\text{BiTeI}$）中通过DFT计算得到验证。 我们提出一个最小轨道导出的紧束缚模型来计算二维晶格中的电子波函数。 我们展示了波函数的轨道成分除了在自旋极化带中常见的自旋切换外，还表现出轨道纹理切换。 这种轨道纹理切换由三个主要特性决定：局部或全局反演对称性破缺、强自旋轨道耦合以及非局域物理（电子位于晶格上）。 使用我们的模型，我们证明轨道纹理切换是普遍存在的，并应在许多实际系统中预期到。 带的轨道杂化是理解这些材料独特波函数特性的关键方面，而这个最小模型有助于建立驱动这些杂化的量子微扰。