Dresden 2017 – wissenschaftliches Programm
CPP 30.9: Vortrag
Mittwoch, 22. März 2017, 11:45–12:00, HSZ 201
Spin Transport in Helical Systems — •Matthias Geyer1,2, Rafael Gutiérrez1, Stefan Siegmund3, and Gianaurelio Cuniberti1,2 — 1Institute for Materials Science, TU Dresden, 01062 Dresden, Germany — 2Dresden Center for Computational Materials Science, TU Dresden, 01062 Dresden, Germany — 3Center for Dynamics, TU Dresden, 01062 Dresden, Germany
Various experiments have shown strong spin selectivity in chiral molecules like DNA at room temperature. Since atomic spin orbit coupling alone is insufficient to explain the effect's magnitude, a relation to the helical geometry has been suggested. We want to provide a better understand of the underlying mechanisms by analytically and numerically investigating suitable models for electrons in helical systems with spin orbit coupling.
We follow two complementary approaches: a generic and simplified model to study the bare influence of the helical geometry and a more realistic one to calculate the effect for specific molecules. The former starts with a 3D continuum model with helix-shaped confinment from which an effective 1D Hamiltonian is derived using adiabatic perturbation theory. For the ladder an effective tight-binding model is derived from the microscopic Hamiltonian of a specific molecule. Incoherent transport calculations are performed for both models using master equations with dephasing, accounting for decoherence due to the coupling to vibrational degrees of freedom arising from structural fluctuation.