Direct Imaging of the Spin Asymmetry of the Au(111) Surface State

DISpin detector shows Rashba splitting

In this joint project the direct imaging spin detector technology has been lifted to a new level together with the group of Liu Chang from South University of Science and Technology. The introduction of the patented spin rotator lens into the optics of the direct imaging spin detector DISpin allows to measure the spin asymmetry function from an iridium scattering target with high ultimate sensitivity and efficiency.

The DI Spin detector utilizes spin-orbit interaction between electrons and a heavy metal target at low scattering energies to enhance the scattering probability of one spin direction from a spin polarized electronic state. The scattering target transfers an angular resolved electronic image at 45° off the direct beam path after passing through a hemispherical analyzer or momentum microscope. In this second beam path an image of the electronic band structure can be acquired, whose intensity is enhanced or suppressed depending ion the spin polarization in the sample.

The detected spin orientation can be chosen in two ways: either by setting the scattering energy to a value sensitive to spin-up or spin-down, with the drawback of slightly different scattering probabilities for spin-up/spin-down electrons. Or the detected spin orientation can be rotated by 180° with a spin rotator lens that allows to change the spin orientation at identical scattering energies and thus scattering probabilities.

We would like to thank Liu Chang for the excellent collaboration in this project and his continuous trust in this development.