Dresden 2014 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 19: Poster I

MA 19.16: Poster

Dienstag, 1. April 2014, 13:00–15:30, P1

Momentum Microscopy (k-PEEM) with Time-of-Flight Dispersion and Imaging Spin Filter — S. Chernov¹, •K. Medjanik¹, F. Schertz¹, D. Panzer¹, H.J. Elmers¹, C. Tusche², A. Krasyuk², J. Kirschner², and G. Schönhense¹ — ¹JGU, Inst. für Physik, D-55099 Mainz — ²MPl für Mikrostrukturphysik, D-06120 Halle

Direct parallel imaging of momentum space is a highly effective method for electronic bandstructure mapping [1]. This approach utilizes the special imaging properties of a cathode-lens, aiming at an ultimate resolution in k-space. In the present work we employ a time-of-flight section as imaging energy filter in combination with a 3D (x,y,t)-resolving delay line detector. Further, an imaging spin filter of Ir(001) type [2] is integrated. The ToF k-microscope detects a certain energy interval in parallel. Cuts through k-space are obtained from the full data set via the corresponding flight-time condition. The spin information can be obtained by switching between spin-integral and spin-filtered branches of the microscope. In the spin-selective branch momentum conservation in the LEED process ensures sharp images with very high signal-to-background discrimination (owing to the ToF filter) and very high spatial resolution. High spin contrast of >70% has been found [2], in good agreement with recent results on Au-covered Ir(100) [3]. First measurements employ a fs laser for excitation, the status of the experiment is reported. Funded by BMBF (05K12UM2 and 05K12EF1).

[1] A. Winkelmann et al., PRB 86 (2012) 085427;

[2] D. Kutnyakhov et al., Ultramicroscopy 130 (2013) 63;

[3] J. Kirschner et al., PRB 88 (2013) 125419