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Electro-optic investigation of the Coherent Hall Effect in semiconductor superlattices

Elektrooptische Untersuchung des kohärenten Hall-Effekts in Halbleiterübergittern
: Hummel, A.B.; Blöser, C.; Bauer, T.; Roskos, H.G.; Kosevich, Y.; Köhler, K.


Physica status solidi. B 242 (2005), No.6, pp.1175-1178
ISSN: 0031-8957
ISSN: 0370-1972
Journal Article
Fraunhofer IAF ()
III-V Halbleiter; III-V semiconductor; superlattice; Übergitter; optical spectroscopy; optische Spektroskopie

After the first observation of the Coherent Hall Effect in a GaAs/Al(0.3)Ga(0.7)As superlattice by means of THz-emission spectroscopy, the dynamics of impulsively excited electron wavepackets in crossed electric and magnetic fields has now been investigated in more detail by reflective electro-optic sampling (REOS). In agreement with the predictions of a semiclassical model, the experiments show the existence of two strictly separated regimes of charge-carrier motion depending on the ratio E/B of applied electric and magnetic field. Both, the magneto-Bloch regime for dominating electric field and the cyclotron-like regime of motion for dominating magnetic field, exhibit a characteristic frequency dependence of the wavepacket oscillations on the external fields. The REOS measurements supplement our results achieved by THz-emission spectroscopy by covering a much larger range of experimental parameters because REOS is not affected by absorption by the cryostat windows of our set-up as is the THz radiation at frequencies above 2 THz, and the detection of high oscillation frequencies is possible.