Berlin 2018 – scientific programme

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TUT: Tutorials

TUT 3: Spin-Orbit Coupling

TUT 3.2: Tutorial

Sunday, March 11, 2018, 16:45–17:30, H 1012

From the Spin Hall Effect to the Quantum Spin Hall Effect — •Hartmut Buhmann — Physikalisches Institut, Universität Würzburg, Würzburg, Germany

Each Hall effect appears to show up with a quantum version where the related conductance is quantized. In solid state materials spin orbit interaction provides a source which leads to a distinct charge separation. In this case the charges deflected to the sides perpendicular to a current flow are characterized by an opposite spin polarization referred to a spin Hall effect. In narrow gap materials spin orbit interaction can lead to a bulk band inversion. In those materials an opposite spin current is observed at the edge of the sample. Due to a quantized charge current this effect is call the quantum spin Hall effect. In this lecture the consequences of a strong spin orbit interaction in semiconductor materials are discussed. Since the spin orbit effect is strongest in narrow gap materials containing heavy elements I will focus here on transport experiments and HgTe quantum well systems which can be viewed as a prototype material for the realization of the spin Hall [1] and quantum spin Hall effect [2].

[1] C. Brüne et al., Nature Physics, 8, 485 (2012).

[2] König et al., Science 318, 766 (2007).