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TT: Fachverband Tiefe Temperaturen
TT 45: Spintronics (incl. Quantum Dynamics)
(Joint session of MA, HL and TT organized by MA)
TT 45.7: Talk
Wednesday, March 9, 2016, 11:15–11:30, H32
Ultra-long electron and hole spin lifetimes in monolayer WSe2 — Sammy Pissinger, •Robin de Winter, Christopher Franzen, Manfred Ersfeld, Sebastian Kuhlen, Christoph Stampfer, and Bernd Beschoten — 2nd Institute of Physics and JARA-FIT, RWTH Aachen University, Germany
There is strong interest in optical generation and detection of valley spin polarizations in transition metal dichalcogenides. We report on time-resolved two color pump probe Kerr rotation measurements on mechanically exfoliated monolayer WSe2 crystals. We find electron and hole spin lifetimes of up to 100 ns at low temperatures. These values are in good agreement with exciton lifetimes extracted from all-optical time-resolved reflectivity indicating that the spin lifetimes are limited by exciton recombination times in our crystals. Electron spin precession in Voigt geometry furthermore reveals inhomogeneous spin dephasing caused by a large spread in the local g factors.