33 research outputs found
Origin of the photoemission final-state effects in Bi2Sr2CaCu2O8 by very-low-energy electron diffraction
Very-low-energy electron diffraction with a support of full-potential band
calculations is used to achieve the energy positions, K// dispersions,
lifetimes and Fourier compositions of the photoemission final states in
Bi2Sr2CaCu2O8 at low excitation energies. Highly structured final states
explain the dramatic matrix element effects in photoemission. Intense c(2x2)
diffraction reveals a significant extrinsic contribution to the shadow Fermi
surface. The final-state diffraction effects can be utilized to tune the
photoemission experiment on specific valence states or Fermi surface replicas.Comment: 4 pages, 3 Postscript figures, submitted to Phys. Rev. Lett; major
revision
Erratum Ground state potential energy surfaces around selected atoms from resonant inelastic x ray scattering
Scientific Reports6 20054; doi 10.1038 srep20054; published online 29 January 2016; updated 30 June 2017The original HTML version of this Article listed an incorrect volume number. This has now been corrected in the HTML version; the PDF version was correct at the time of publicatio
Two-domains bulklike Fermi surface of Ag films deposited onto Si(111)-(7x7)
Thick metallic silver films have been deposited onto Si(111)-(7x7) substrates
at room temperature. Their electronic properties have been studied by using
angle resolved photoelectron spectroscopy (ARPES). In addition to the
electronic band dispersion along the high-symmetry directions, the Fermi
surface topology of the grown films has been investigated. Using ARPES, the
spectral weight distribution at the Fermi level throughout large portions of
the reciprocal space has been determined at particular perpendicular
electron-momentum values. Systematically, the contours of the Fermi surface of
these films reflected a sixfold symmetry instead of the threefold symmetry of
Ag single crystal. This loss of symmetry has been attributed to the fact that
these films appear to be composed by two sets of domains rotated 60 from
each other. Extra, photoemission features at the Fermi level were also
detected, which have been attributed to the presence of surface states and
\textit{sp}-quantum states. The dimensionality of the Fermi surface of these
films has been analyzed studying the dependence of the Fermi surface contours
with the incident photon energy. The behavior of these contours measured at
particular points along the Ag L high-symmetry direction puts forward
the three-dimensional character of the electronic structure of the films
investigated.Comment: 10 pages, 12 figures, submitted to Physical Review
Unoccupied Band Structure of Layered Materials by Very-Low-Energy Electron Diffraction: Implications in Photoemission
Heydemann interpolation correction for energy linearization of soft X ray monochromators
Material science research in the soft X ray regime at the Swiss Light Source accommodates five beamlines where the monochromators rely on in vacuum angular encoders for positioning mirror and gratings. Despite the factory calibration of the quadrature signals from these rotary encoders, the energy linearization for spectroscopic data requires accurate calibration of the encoder quadrature signals. We characterize the interpolation errors and describe the Heydemann correction algorithm for the quadrature signals for improving the energy linearization on a scale comparable with the incremental encoder interpolation interval. Experimental data are shown where such errors produce sizeable effects in soft X ray spectroscopy and for which the correction algorithm efficiently improves the short range non linearit
Photoemission spectroscopy in metals
Photoemission spectroscopy in metals : band structure - Fermi surface - spectral function / R. Claessen ... - In: Journal of electron spectroscopy and related phenomena. 100. 1999. S. 191 ff