Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 89: Surface Dynamics II
O 89.9: Talk
Friday, March 15, 2013, 12:30–12:45, H33
2PPE-measurement with an angle-resolving time-of-flight spectrometer — •Thomas Kunze1,2, Dominic Lawrenz1, Jens Kopprasch1, Martin Teichmann1, Thorsten U. Kampen2, and Martin Weinelt1 — 1Freie Universität Berlin, Berlin, Germany — 2SPECS GmbH, Berlin, Germany
To increase the efficiency of electronic structure measurements we developed in cooperation with SPECS an angle-resolving time-of-flight spectrometer.
The instrument allows to measure the kinetic electron energy as a function of the two-dimensional parallel crystal momentum (E vs. kx∥ and ky∥) without rotating the sample. The electron lens in front of the detector allows angle or spacial resolved measurements.
While developing this new machine a number of issues had to be addressed. We developed a proper way to simulate the electron trajectories, found a method to suppress secondary electrons and established a suitable measurement procedure. The use of the instrument is not as common as measurements with a hemispherical analyzer. We will point out the advantages and disadvantages of the method.
The talk will cover the alignment of the spectrometer itself and relative to the sample and the working principle of the detector gating unit.
Finally, we will report on our two-photon photoemission studies of Cu(111) and Cu(1 1 11) which illustrate the potential of time-of-flight electron spectroscopy.