Berlin 2015 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 67: Topological insulators I (MA with HL/TT)
HL 67.3: Talk
Thursday, March 19, 2015, 10:00–10:15, EB 202
Momentum resolved spin dynamics of bulk and surface excited states in the topological insulator Bi2Se3 — C Cacho1, A Crepaldi2, M Battiato3, J Braun5, H Ebert5, K Hricovini4, •Jan Minar5,6, and F Parmigiani2 — 1Central 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