1^2 ARPES ultra high resolution photoemission instrument /UE112

The ARPES One-Square instrument is dedicated to high-resolution angle-resolved photoelectron spectroscopy. It is installed at the UE112 PGM-2a-1^2 beamline which is based on low-energy collimated plane-grating monochromator with normal incidence option. The beamline delivers photons in the energy range from 10 to 250 eV. Energy resolution for photon energies below 100 eV can be tuned down to 1 meV. The horizontal dimension of the focal spot is about 150 μm, its vertical dimension depends on the exit slit setting but is typically about 20 μm.

The instrument is equipped with a very high-resolution electron energy analyzer and attached to a beamline providing photons in the energy range from 10 – 250 eV with high resolution and full control over the polarization. A precise 6-axes cryomanipulator combined with an electron analyzer Scienta R8000, operated in parallel angular detection mode, allows for accurate band structure mapping. The versatility of the system is extended by exerting a very broad spectrum of in-situ sample treatment techniques.

Selected Applications:

• 2D materials and graphene
• Topological insulators, Weyl semimetals, Dirac nodal line materials
• Metallic single crystals with flat and vicinal surfaces
• High-temperature superconductors
• Metal halide perovskites (inorganic)

Model of ARPES One-Square

Methods

LEED, ARPES, UPS, XPS

Remote access

not possible

The 1² ARPES instrument is the more versatile sibling of the low-temperature 1³ ARPES instrument. While it receives light from the same beamline and is equipped with a very high resolution electron energy analyzer, it sheds the ability to reach the lowest temperatures in favor of a much more flexible 6 axes manipulator.

The versatility of the system is furthered by utilization of Omicron/Flag-style sample holders as sample carrier, which make it compatible with varous scientific instruments at HZB or at home institutes of BESSY users. Respectively, compatibility with standard vacuum suitcases (e.g. Ferrovac) is ensured.

Key features of the endstation:

• High-resolution angle-resolved photoelectron spectroscopy (ARPES) allowing for accurate and detailed full photoemission mapping of the band structure of samples
• Precise computer-controlled full 6-axes cryomanipulator with temperature down to 15K
• Low energy electron diffraction (LEED)
• Utilization of Omicron/Flag-style sample carriers as a standard
• Preparative sample heating up to 2300K
• Sample cleaving by top-post at low or elevated temperature
• Quadrupole mass spectrometer
• Gateable ports for user devices or material evaporators
• Thin film in-situ deposition on hot or cold sample
• Source of alkali materilas for electron doping is always available by default
• Load-lock for rapid loading of the samples from atmosphere