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MA: Fachverband Magnetismus

MA 42: Topological Insulators I (jointly with DS, HL, O, TT)

MA 42.3: Vortrag

Donnerstag, 19. März 2015, 10:00–10:15, EB 202

Momentum resolved spin dynamics of bulk and surface excited states in the topological insulator Bi2Se3C Cacho1, A Crepaldi2, M Battiato3, J Braun5, H Ebert5, K Hricovini4, •Jan Minar5,6, and F Parmigiani21Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell, United Kingdom — 2Elettra - Sincrotrone Trieste, Italy — 3Institute of Solid State Physics, Vienna University of Technology — 4Universite de Cergy-Pontoise, France — 5LMU München, Germany — 6University of West Bohemia, Plzen, Czech Rep.

The prospective of optically inducing a spin polarized current for spintronic devices has generated a vast interest in the out-of-equilibrium electronic and spin structure of topological insulators (TIs). In this presentation we prove that only by measuring the spin intensity signal over several order of magnitude in spin, time and angle resolved photoemission spectroscopy (STAR-PES) experiments is it possible to comprehensively describe the optically excited electronic states in TIs materials. The experiments performed on Bi2Se3 reveal the existence of a Surface-Resonance-State in the 2nd bulk band gap interpreted on the basis of fully relativistic ab-initio spin resolved photoemission calculations. Remarkably, the spin dependent relaxation of the hot carriers is well reproduced by a spin dynamics model considering two non-interacting electronic systems, derived from the excited surface and bulk states, with different electronic temperatures. For more details see: Cacho et all.,
http://arxiv.org/abs/1409.5018

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DPG-Physik > DPG-Verhandlungen > 2015 > Berlin