Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 11: Methods: Scanning probe techniques II

O 11.3: Talk

Monday, March 22, 2010, 15:30–15:45, H32

Deconvolution of the local density of states from constant-current tunneling spectra — •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 to analyze the local density of states (LDOS) of a sample. An undoubted advantage over I-V measurements at constant tip-sample separation is a wider accessible range of bias especially on delicate samples such as those involving organic molecules. While now-a-days numerical methods are available to include effects of the tunnelling barrier and even to deconvolve the LDOS of tip and sample from I-V measurements [1], for z-V spectroscopy such an analysis is still missing. Recently, Ziegler et al. applied an adopted method to remove effects of the tunnelling barrier from z-V measurements [2]. Here, we introduce an adopted method from [1] to obtain a deconvolution of the LDOS from z-V measurements taken at different set currents on Nb(110) at low temperature.

[1] B. Koslowski, H. Pfeifer, P. Ziemann, PRB 80, 165419 (2009).

[2] M. Ziegler, N. Néel, A. Sperl, J. Kröger, R. Berndt, Phys. Rev. B 80, 125402 (2009).