Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 12: Surface dynamics

O 12.11: Talk

Monday, March 26, 2012, 18:30–18:45, H 2013

Ultrafast Electron Dynamics in the Topological Insulator Material Bi₂Se₃ — •Patrick Kirchmann^1,2, Jonathan Sobota^2,3,4, Shuolong Yang^2,3,4, James Analytis^2,3, Yulin Chen^2,3,4, Ian Fisher^2,3, and Zhi-Xun Shen^2,3,4 — ¹Fritz Haber Institute of the Max Planck Society, Department of Physical Chemistry, Faradayweg 4-6, D-14195 Berlin, Germany — ²Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA — ³Geballe Laboratory for Advanced Materials, Department of Applied Physics, Stanford University, Stanford, CA 94305, USA — ⁴Department of Physics, Stanford University, Stanford, CA 94305, USA

Using femtosecond time- and angle-resolved photoemission spectroscopy, we investigated the non-equilibrium electron dynamics of the topological insulator Bi₂Se₃. We studied p-type Bi₂Se₃, in which the metallic Dirac surface state and bulk conduction bands are unoccupied. Optical excitation leads to a meta-stable population at the bulk conduction band edge, which feeds a population of the surface state persisting for >10 ps. This unusually long-lived population of a metallic Dirac surface state with spin texture may present a channel in which to drive transient spin-polarized currents.