Spatial Dynamics of Wave Packets in Semiconductor Heterostructures

Dirk Meinhold

AutorIn

Dirk Meinhold

Titel

Spatial Dynamics of Wave Packets in Semiconductor Heterostructures

Zitierfähige Url:

https://nbn-resolving.org/urn:nbn:de:swb:14-1120744780310-59904

Übersetzter Titel (DE)

Räumliche Wellenpaketdynamik in Halbleiterheterostrukturen

Datum der Einreichung

03.02.2005

Datum der Verteidigung

13.05.2005

Abstract (EN)

This thesis presents the first study of the damping of a Bloch oscillating wave packet by Zener tunneling to above-barrier states [1]. We investigate the time evolution of an below-barrier subband Wannier-Stark wave packet in a strongly coupled GaAs/AlGaAs superlattice (SL) with shallow quantum well barriers by optical interband spectroscopy. We use a sub-100 fs homodyne pump-probe technique which is sensitive to the intraband polarization. The presented experimental data unambiguously show an electric field-dependent continuous decrease of the intraband coherence time. Besides the continuous field-induced damping of the intraband polarization, we observe the signature of resonant Zener tunneling of a Bloch oscillating wave packet between discrete states belonging to below and above-barrier bands. This coupling manifests itself as a revival of the intraband polarization [2]. The experiment is modelled in two aspects. First, in a 1D single-particle calculation the wave functions the BO wave packet is composed of are derived. Here, the inter-subband dynamics are found to be given by the energetic splitting between nearly-degenerate below and above-barrier states. The wave packet tunnels from the below-barrier band to the above-barrier band while remaining coherently oscillating. At this time, it is spatially spread over more than 100 nm...

Freie Schlagwörter (DE)

Bloch Oszillationen, Feldinduzierte Delokalisierung, Pump-Probe Spektroskopie, Resonanter Zener-Durchbruch, Wellenfunktionstomographie, Wellenpaketdynamik, Zener-Durchbruch, Übergitter

Freie Schlagwörter (EN)

Bloch oscillation, Pump probe spectroscopy, Zener breakdown, field-induced delocalisation, field-induced delocalization, graded superlattice, resonant Zener breakdown, superlattice, wave function tomography, wave packet dynamics

Klassifikation (DDC)

530

Klassifikation (RVK)

UF 5000

Normschlagwörter (GND)

Delokalisierung, Dynamik, Optische Spektroskopie, Schwingung, Tomographie, Wellenfunktion, Wellenpaket, Zener-Effekt, Übergitter

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