Departamento Física de Materiales, Universidad Complutense de Madrid, Madrid 28040, Spain.
J Phys Condens Matter. 2011 Aug 3;23(30):305006. doi: 10.1088/0953-8984/23/30/305006. Epub 2011 Jul 6.
For the non-magnetic system of Ag films on Ru(0001), we have measured the circular dichroism of photoelectrons emitted along the surface normal, the geometry typically used in photoemission electron microscopy. Photoemission spectra were acquired from micrometer-sized regions having uniformly thick Ag films on a single, atomically flat Ru terrace. For a single Ag layer, we find a circular dichroism that exceeds 6% at the d-derived band region around 4.5 eV binding energy. The dichroism decreases as the Ag film thickness increases to three atomic layers. We discuss the origin of the circular dichroism in terms of the symmetry lowering that can occur even in normal emission.
对于 Ru(0001) 上 Ag 薄膜的非磁性体系，我们测量了沿表面法线发射的光电子的圆二色性，这是通常用于光电子发射电子显微镜的几何形状。光电子能谱是从具有均匀厚 Ag 薄膜的单个原子级平坦 Ru 梯台上的微米级区域中获取的。对于单个 Ag 层，我们发现圆二色性在大约 4.5 eV 结合能的 d 衍生能带区域超过 6%。随着 Ag 膜厚度增加到三个原子层，二色性减小。我们根据即使在正常发射时也可能发生的对称性降低来讨论圆二色性的起源。
