Department of Surface and Nanostructures Physics

Low energy electron microscopy (LEEM) is a method that provides real‑time observation of surface science phenomena like morphology, topography, structure, phase transition, thin film growth, segregation and diffusion, to name a few. In LEEM, low energy electrons reflected from the sample surface are used to create a magnified image of the surface captured by CCD camera. Besides the real space imaging mode, the microscope in LEED mode allows the observation of the diffraction pattern of the sample surface formed by elastically backscattered low energy electrons. Additionally, in µLEED mode the illumination aperture can be used to reduce the size of the electron spot on the sample surface. In this configuration, the observed diffraction pattern origins from a small selected area of the sample. Combination of LEED and LEEM technique allows to choose which diffraction spot will be used to create real space image. Such imaging, called dark field imaging, produces a contrast based on the difference in structure of the sample surface. Our LEEM is also equipped with Spin‑polarized electron gun which utilizes a GaAs cathode activated by Cs and O2 and illuminated by circular polarized infrared laser as a source of the spin polarized electrons. The polarization of electron beam can be freely adjusted in both azimuthal and polar angles. Spin-polarized operating mode (SP-LEEM) can be used to investigate magnetic properties of the sample, such as domain structure and magnetic anisotropy.