Magnetic Orbital Quantum Number Measurements: Phenomena and Applications

Core-level photoelectron diffraction provides element-specific atomic structure information. Forward focusing peaks (FFPs) indicate the directions of atoms surrounding a photoelectron emitter atom. When a core level is excited by circularly polarized light, angular momentum of light is transferred to an emitted photoelectron, which can be confirmed by the parallax shift measurement of FFP direction. Here I report the new observation and quantitative analysis of the angular momentum transfer from light to Auger electrons, and compare them with the photoelectron cases. Angularmomentum-polarized Cu LMM Auger electrons at the L absorption threshold, where the excited core electron is trapped at the conduction band, were detected. By setting an analyzer at the corresponding position in the FFP direction, the Auger electron with a specific angular momentum can be selectively detected. In the case of magnetic materials, circular dichroism in the X-ray absorption intensity was observed together with angular momentum transfer (parallax shift) effect.