Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 16: Scanning probe methods I
O 16.1: Vortrag
Montag, 14. März 2011, 15:00–15:15, WIL C307
Deconvolution of the local density of states from z-V spectroscopy and its application to Nb(110) — •Holger Pfeifer, Berndt Koslowski, and Paul Ziemann — Institut für Festkörperphysik, Universität Ulm, D-89069 Ulm, Germany
In recent years, measurement of the differential conductivity at constant current (z-V spectroscopy) has been established as a powerful tool in scanning tunnelling spectroscopy in order to analyze the local density of states (LDOS) of a sample. However, in contrast to I-V spectroscopy [1], numerical methods are lacking to remove effects of the tunnelling barrier from the measurement and to deconvolve the LDOS of tip and sample. Here we introduce an adopted method from [1] to achieve a deconvolution of the LDOS from z-V measurements. We first demonstrate the deconvolution method using numerical data. Secondly, we apply this method to experimental data obtained on Nb(110) at low temperature and compare the results with the differential barrier height (d2I/dVdz/ dI/dV)2 [2]. We show that the differential barrier is much more sensitive to changes in the DOS than the commonly used (integral) barrier height (dI/dz/I)2.
[1] B. Koslowski, H. Pfeifer, P. Ziemann, PRB 80, 165419 (2009).
[2] B. Koslowski et al. PRB 75, 035421 (2007).