Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 8: Surface State Spectroscopy I
O 8.3: Invited Talk
Monday, March 7, 2016, 11:00–11:30, H4
Momentum Microscopy with Time-of-Flight Analysis and Spin Filtering: Direct Imaging of k-Space Objects and Spin Textures — •Gerd Schönhense — Institut für Physik, Johannes Gutenberg-Universität, 55128 Mainz, Germany
Momentum microscopy has recently set impressive benchmarks, in particular in combination with an imaging spin filter [1]. In Mainz we develop a modified approach based on time-of-flight parallel energy detection instead of dispersive analyzers [2]. A fast delay-line detector (> 5 Mcps, 150 ps resolution) provides 3D data recording. The state of development and first scientific results will be reported. The spin-filtered mode was explored at BESSY II (U125-2 NIM) for determination of P(EB,kx,ky) spin textures with more than 104 data points simultaneously. Surface and bulk bands of the topological ferroelectric GeTe(111) show Rashba-type spin textures [3]. For W(110) three surface bands with anomalous spin textures were found [4], one of which has been studied before [5]. In the soft-X range (PETRA III, P04) we observed sharp 3D band patterns with giant CDAD asymmetries for Ir and W up to hv=1300eV at T=30K, with 105-106 data voxels simultaneously. Variation of photon energy yielded I(EB,kx,ky, kz) datasets for Fermi surface tomography. Strategies to utilize multibunch modes are explored at MAXLAB (Lund, Sweden).
[1] Tusche et al., Ultramicroscopy DOI: 10.1016/j.ultramic.2015.03.020 (2015); [2] Schoenhense et al., JESRP 200 (2015) 94 ; [3] Elmers et al., this conf.; [4] Kutnyakhov et al., this conf.; [5] Miyamoto et al., PRL 108 (2012) 066808.