Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 8: Electron and spin dynamics

O 8.3: Vortrag

Montag, 26. März 2012, 11:00–11:15, A 060

Electronic lifetimes in a Bi quantum well with Rashba spin-splitting — •Svenja Vollmar, Andreas Ruffing, Sebastian Jakobs, Alexander Baral, Mirko Cinchetti, Stefan Mathias, Martin Aeschlimann, and Hans Christian Schneider — University of Kaiserslautern

2-photon photoemission spectroscopy and ab-initio calculations suggest that a part of the band structure of a Bi monolayer (quantum well) on a Cu(111) substrate is well described [1] by a simple Rashba Hamiltonian, which includes the effects of the spin-orbit interaction together with an asymmetric confinement potential of a quantum-well. The understanding of the consequences of the Rashba spin-split electronic bands on the electronic spin dynamics is of general importance for spin transport and diffusion lengths in such systems.

Using a combination of 1-photon and 2-photon photoemission spectroscopy, we determine the energy and momentum dependent electronic lifetimes in the Bi quantum well, and find a plateau around the intersection of the Rashba bands. To understand this characteristic energy and momentum dependence, we calculate the electronic lifetime due to carrier-carrier scattering in a simple model of a 2D electron gas including a Rashba interaction with effective Rashba parameters derived from experiment. We reproduce the observed plateau in the lifetimes using this model, and explain this behavior by a change of available scattering phase space for electrons below and above the intersection of the Rashba bands.

[1] S. Mathias et al., Phys. Rev. Lett. 104, 066802 (2010)