Regensburg 2013 – scientific programme

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O: Fachverband Oberflächenphysik

O 71: Surface Magnetism (jointly with MA)

O 71.4: Talk

Thursday, March 14, 2013, 16:00–16:15, H3

Constant current contrast in spin-polarized STM — •Krisztian Palotas — Budapest University of Technology and Economics, Department of Theoretical Physics, Budapest, Hungary

This work is concerned with the theoretical description of the contrast, i.e., the apparent height difference between two lateral surface positions on constant current spin-polarized scanning tunneling microscopy (SP-STM) images.

We propose a method [1] to predict the bias voltage dependent magnetic contrast from single point tunneling current or differential conductance measurements, without the need of scanning large areas of the surface. Depending on the number of single point measurements, the bias positions of magnetic contrast reversals and of the maximally achievable magnetic contrast can be determined. We validate this proposal by simulating SP-STM images on a complex magnetic surface employing a recently developed approach based on atomic superposition [2]. Furthermore, we show evidence that the tip electronic structure and magnetic orientation have a major effect on the magnetic contrast. Our theoretical prediction should inspire experimentalists to considerably reduce measurement efforts for determining the bias dependent magnetic contrast on magnetic surfaces.

This research was supported by the OTKA PD83353, K77771, TAMOP-4.2.2.B-10/1-2010-0009 projects, and a Bolyai Grant.

[1] K. Palotas, arXiv:1207.3995 (2012).

[2] K. Palotas et al., Phys. Rev. B 83, 214410 (2011); Phys. Rev. B 84, 174428 (2011); Phys. Rev. B 85, 205427 (2012).