Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 79: Scanning Probe Techniques: STM
O 79.1: Talk
Thursday, March 19, 2015, 10:30–10:45, HE 101
Landau quantization in graphite studied by STM in a 30 Tesla magnet — •Bas Hendriksen1, Suruchi Singh1,2, Wei Tao2, Jan Gerritsen1, Uli Zeitler2, Peter Christianen2, and Jan Kees Maan2 — 1Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands — 2High Field Magnet Laboratory and Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
Experiments in high field magnet laboratories play an important role in the discovery of new electronic phenomena in solid state materials. Superconducting laboratory magnets are typically limited to fields up to 20 Tesla and it requires resistive Bitter magnets at dedicated large-scale facilities to go to fields as high as 37 Tesla. In this talk I will present our pioneering experiments with a scanning tunneling microscope, which operates in the 30 Tesla Bitter magnets of the High Field Magnet Laboratory (HFML) user facility in Nijmegen. This STM provides access to atomic- and nanoscale physics in the high magnetic field regime, where the magnetic length is of the order of a few nanometers and energy level splitting is significant.
I will demonstrate the STM's performance in the noisy environment of the magnets (140l/s cooling water, 40kA magnet current). I will show our first results of Landau level spectroscopy in a graphite sample at 4.2K, which exhibits the characteristics of Landau levels in graphene. I will discuss how this is a first step towards solving the mystery of the quantum Hall effect in graphene at room temperature (K.S. Novoselov et al. Science 315 (2007) 1379).