Open AccessSoft‐X‐ray ARPES facility at the ADRESS beamline of the SLS: concepts, technical realisation and scientific applications
Author(s) -
Strocov V. N.,
Wang X.,
Shi M.,
Kobayashi M.,
Krempasky J.,
Hess C.,
Schmitt T.,
Patthey L.
Publication year - 2014
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577513019085
Subject(s) - beamline , angle resolved photoemission spectroscopy , physics , angular resolution (graph drawing) , photon , photoexcitation , optics , photon energy , synchrotron radiation , atomic physics , electronic structure , beam (structure) , condensed matter physics , excited state , mathematics , combinatorics
Soft‐X‐ray angle‐resolved photoelectron spectroscopy (ARPES) with photon energies around 1 keV combines the momentum space resolution with increasing probing depth. The concepts and technical realisation of the new soft‐X‐ray ARPES endstation at the ADRESS beamline of SLS are described. The experimental geometry of the endstation is characterized by grazing X‐ray incidence on the sample to increase the photoyield and vertical orientation of the measurement plane. The vacuum chambers adopt a radial layout allowing most efficient sample transfer. High accuracy of the angular resolution is ensured by alignment strategies focused on precise matching of the X‐ray beam and optical axis of the analyzer. The high photon flux of up to 10 13 photons s −1 (0.01% bandwidth) −1 delivered by the beamline combined with the optimized experimental geometry break through the dramatic loss of the valence band photoexcitation cross section at soft‐X‐ray energies. ARPES images with energy resolution up to a few tens of meV are typically acquired on the time scale of minutes. A few application examples illustrate the power of our advanced soft‐X‐ray ARPES instrumentation to explore the electronic structure of bulk crystals with resolution in three‐dimensional momentum, access buried heterostructures and study elemental composition of the valence states using resonant excitation.