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When mapping spatially resolved photoemission intensity for electron kinetic energy corresponding to Fermi energy, one obtains a spherical cut through a three-dimensional Fermi surface of a metal. At the APE-INFM beamline at Elettra, we developed an automated method of measuring the Fermi surface cuts for a large number of photon energies and putting them together in order to reconstruct the three-dimensional Fermi surface. The energy and k(parallel to) (momentum parallel to the surface) resolution are set by the monochromator and energy analyzer properties, while the k(perpendicular to) (momentum perpendicular to the surface) resolution depends on the photon energy step chosen for obtaining subsequent data sets. By 3D interpolation of the data, one obtains the k-space tomography of the constant initial state surfaces (e.g. of the Fermi surface). From the tomography, one can retrieve true k(x), k(y), k(z) resolved maps. Besides de Haas van Alphen (dHvA) oscillations, this method is the most direct way for the determination of the Fermi surfaces. A set of data on the Fermi surface of Be(0 0 0 1) is presented and compared to dHvA data and theory. (C) 2007 Elsevier B.V. All rights reserved.

The discontinuity in the lattice periodic potential at surfaces often leads to the creation of new electronic surface states. We developed a photoemission based Fermi surface tomography whose surface sensitivity allowed us to quantify the charge redistribution on the Be(0001) surface. The volume enclosed by the bulklike Fermi surface is significantly reduced at the surface, consistent with the charge transfer to the two surface states as estimated from the area within their two-dimensional Fermi contours. This result represents the first quantification of the charge redistribution on a natural surface termination.