Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 77: Electronic Structure and Spin-Orbit Interaction III
O 77.11: Vortrag
Donnerstag, 14. März 2013, 18:30–18:45, H33
Probing current noise and topography in low-temperature scanning tunneling microscopes at sub-molecular resolution — •Markus Herz, Samuel Bouvron, Elizabeta Ćavar, Mikhail Fonin, and Elke Scheer — Department of Physics, University of Konstanz, 78457 Konstanz
Noise studies have become an active field in mesoscopic physics because they reveal a variety of additional information about electronic correlations [1].
We probe the current noise in low-temperature scanning tunneling microscopes (STM). The measurement setup is modified for extracting the current noise and its spectral density without the necessity of double wiring and performing cross correlation [2] and without going to high frequency measurements [3].
We show simultaneous measurements of the tunneling current and its noise in a low-temperature STM [4] with a very high thermal, mechanical and electronic stability.
In first experiments, the Fano factor F=1 is observed to be a sharp lower limit for the current noise scaling when imaging sub-molecular details of clusters produced on a metallic surface at a tunneling conductance of ≃ 10−4 G0, and the noise power is not correlated with the topographic signal.
[1] Y. Blanter and M. Büttiker, Physics Report, 336 (2000)
[2] B. Ludoph et al., Phys. Rev. Lett. 82, 1530 (1999)
[3] R. Chen et al., Phys. Rev. B 85, 235455 (2012)
[4] C. Debuschewitz et al., J. Low. Temp. Phys. 147, 525 (2007)