标题： Mn$_{1-x}$Ge$_x$Bi$_2$Te$_4$中自旋纹理可调性通过改变Ge浓度 显示英文标题

标题： Spin texture tunability in Mn$_{1-x}$Ge$_x$Bi$_2$Te$_4$ through varying Ge Concentration

摘要： 自旋分辨的色散依赖关系对于拓扑绝缘体 Mn$_{1-x}$Ge$_x$Bi$_2$Te$_4$在布里渊区的$\bar{\rm K}\bar{\Gamma}\bar{\rm K}'$路径中通过使用激光辐射（激光自旋-ARPES）的自旋和角度分辨光电子能谱进行了研究，其中替代性锗原子的浓度（x 从 0.1 到 0.8）发生了变化，用于面内（$s_x$）和面外（$s_z$）自旋取向。 展示了 Rashba 类态的形成，这些态随着锗浓度的增加而向较低能量移动。 在锗浓度从 50% 到 75% 的区域，这些态对形成的自旋依赖色散的贡献变得占主导地位。 在平面内（$s_y$）自旋极化明显，对于相反的$\pm k_\parallel$方向不对称，这是Dirac锥态所揭示的，而Rashba-like态在平面内（$s_y$）和面外（$s_z$）自旋极化都表现出明显的不对称性。理论计算证实了在BZ的$\bar{\rm K}\bar{\Gamma}\bar{\rm K}'$路径中形成的Rashba-like态的不对称极化，同时适用于平面内和面外自旋取向。 常能图对于类似Rashba态显示在$s_z$方向上有明显的$\bar{\Gamma}\bar{\rm K}$自旋分量，当等高线穿过$\bar{\Gamma}\bar{\rm M}$方向时，其符号会发生变化。 观察到的自旋极化可能会影响基于磁性拓扑绝缘体的自旋器件的发展。 显示英文摘要

摘要： The spin-resolved dispersion dependencies for the topological insulator Mn$_{1-x}$Ge$_x$Bi$_2$Te$_4$ in the $\bar{\rm K}\bar{\Gamma}\bar{\rm K}'$ path of the Brillouin zone were studied by spin- and angle-resolved photoemission spectroscopy using laser radiation (Laser Spin-ARPES) with variation of the concentration of substitutional Ge atoms (x from 0.1 to 0.8) for in-plane ($s_x$) and out-of-plane ($s_z$) spin orientation. The formation of Rashba-like states is shown, which shift to lower energies with increasing Ge concentration. In the region of Ge concentrations from 50% to 75%, the contribution of these states to the formed spin-dependent dispersions becomes predominant. A pronounced in-plane ($s_y$) spin polarization, asymmetric for opposite $\pm k_\parallel$ directions, is revealed for the Dirac cone states, while the Rashba-like states exhibit a pronounced asymmetry in both in-plane ($s_y$) and out-of-plane ($s_z$) spin polarizations. Theoretical calculations confirmed the asymmetric polarization of the Rashba-like states formed in the $\bar{\rm K}\bar{\Gamma}\bar{\rm K}'$ path of the BZ, simultaneously for in-plane and out-of-plane spin orientation. Constant energy maps for Rashba-like states show a pronounced $s_z$ spin component along the $\bar{\Gamma}\bar{\rm K}$ direction, with a sign change as the contour crosses the $\bar{\Gamma}\bar{\rm M}$ direction. The observed spin polarization can influence the development of spin devices based on magnetic topological insulators.