The Bloch beamline is dedicated to high-resolution angle-resolved photoelectron spectroscopy (ARPES), for studying the electronic structure of surfaces and 2D materials. Bloch is optimized for a photon energy range of 10-200eV and features a beam size down to 10μm x 10μm on both endstations. Both linear and circular polarized light can be provided, and (with substantially reduced flux) the beamline can source photon energies up to 1000eV, enabling core level spectroscopy of most elements.
Branchline 1 has an endstation comprehensively configured for ‘standard’ ARPES experiments. Six ultra-high vacuum coupled chambers provide ample opportunities for sample preparation and offline characterization with LEED and STM. The analysis chamber is equipped with a fully motorized six-axis manipulator, with a closed-cycle cryostat capable of arbitrary sample temperatures down to 18K. The electron analyzer is a high-performance DA30 hemispherical analyzer from ScientaOmicron. Here the electronic deflection mode enables Fermi surface mapping without needing to rotate the sample, which combined with the small spot size is highly advantageous for studying small or inhomogeneous samples.
The branchline 2 endstation is dedicated to spin-resolved ARPES measurements, using a high-efficiency VLEED detector and spin rotator package from SPECS capable of resolving all three spin components. The analysis chamber is equipped with a fully motorized four-axis manipulator, with manual adjustment of azimuthal angle possible (“4.5 axis”). The closed-cycle cryostat is capable of arbitrary sample temperatures down to 15K. The electron analyzer is a Phoibos 150 from Specs. Here also electronic deflection mode enables Fermi surface mapping without needing to rotate the sample, and for spin measurements mitigates some of the difficulties caused by having only a 4-axis manipulator.
