Hybrid Photoelectron Momentum Microscope at the Soft X-ray Beamline I09 of the Diamond Light Source

Soft X-ray momentum microscopy of crystalline solids is a highly efficient approach to map the photoelectron distribution in four-dimensional (E, k) parameter space over the entire Brillouin zone. The fixed sample geometry eliminates any modulation of the matrix element otherwise caused by changing the angle of incidence. We present a new endstation at the soft X-ray branch of beamline I09 at the Diamond Light Source, UK. The key component is a large single hemispherical spectrometer combined with a time-of-flight analyzer behind the exit slit. The photon energy ranges from hv = 105 eV to 2 keV, with circular polarization available for hv > 150 eV, allowing for circular dichroism measurements in angle-resolved photoemission (CD-ARPES). A focused and monochromatized He lamp is used for offline measurements. Under k-imaging conditions, energy and momentum resolution are 10. 2 meV (FWHM) and 0. 010 angstroms^-1 (base resolution 4. 2 meV with smallest slits and a pass energy of 8 eV). The large angular filling of the entrance lens and hemisphere (225 mm path radius) allows k-field-of-view diameters > 6 angstroms^-1. Energy filtered X-PEEM mode using synchrotron radiation revealed a resolution of 300 nm. As examples we show 2D band mapping of bilayer graphene, 3D mapping of the Fermi surface of Cu, CD-ARPES for intercalated indenene layers and the sp valence bands of Cu and Au, and full-field photoelectron diffraction patterns of Ge.