Plasmon dispersions in high electron mobility terahertz detectors

Białek, M.; Czapkiewicz, M.; Wróbel, J.; Umansky, V.; Łusakowski, J.

doi:10.1063/1.4886970

Cited by 22 publications

(24 citation statements)

References 29 publications

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“…This argumentation is important in the case of our results because excitations of magnetoplsasmons were found to be the main mechanism of the photoresponse observed in samples investigated. 14,15 The samples used in the present study were processed on a high electron mobility GaAs/AlGaAs heterostructure grown by a molecular beam epitaxy. 15 Hall effect measurements at 4.2 K allowed us to estimate an electron concentration and a mobility to be about 3.0×10 11 cm −2 and 6×10 5 cm 2 /Vs, respectively.…”

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confidence: 99%

Photoresponse of a two-dimensional electron gas at the second harmonic of the cyclotron resonance

et al. 2015

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Terahertz spectroscopy experiments at magnetic fields and low temperatures were carried out on samples of different gate shapes processed on a high electron mobility GaAs/AlGaAs heterostructure. For a given radiation frequency, multiple magnetoplasmon resonances were observed with a dispersion relation described within a local approximation of the magnetoconductivity tensor. The second harmonic of the cyclotron resonance was observed and its appearance was interpreted as resulting from a high frequency, inhomogeneous electromagnetic field on the border of a two-dimensional electron gas with a metallic gate and/or an ohmic contact. In a two-dimensional electron gas (2DEG) subject to a perpendicular magnetic field (B), electrical dipole transitions between Landau levels (LL) are restricted by the selection rule: N → N ± 1, where N = 0, 1, ... is the LL number. However, this strict selection rule was shown to be relaxed in some cases. Observations of harmonics of the cyclotron resonance (CR) were reported in a Si metal-oxide-semiconductor field-effect transistor at a sufficiently high gate polarization.1 They were explained as a result of a simultaneous action of a short-range scattering by charged traps at the Si/SiO 2 interface and the electron-electron scattering.2 Recently, Dai et al. reported on a strong response of a 2DEG at the second harmonic of the cyclotron resonance (2CR).3 The experiments were carried out at temperature (T ) between 0.3 K and 1.4 K on a GaAs/AlGaAs sample with a 2DEG mobility of 3 × 10 7 cm 2 /Vs and at radiation frequency (f ) from 60 GHz to 120 GHz. The 2CR peak was shown to be distinct from microwave-induced resistance oscillations (MIRO) 4 and disappeared at about 1.4 K. A similar observation was reported by Hatke et al. on a 2DEG in a few GaAs/AlGaAs wafers with the electron mobility of the order of 10 7 cm 2 /Vs in experiments carried out at T = 0.5 K or 1.5 K. In a series of papers 5-7 properties of a peak appearing in the photoresponse in a proximity to the 2CR were analyzed in a great detail. It was shown that the peak did not result from the MIRO and that its properties could not be explained within existing theoretical models.In the present paper we report on the observation of a photoresponse of a 2DEG at magnetic fields corresponding to the excitation of the 2CR. There are essential differences between our experiments and the experiments described in Refs. 3, 5-7. First, we investigated a 2DEG which resides in a single GaAs/AlGaAs heterostructure in comparison to modulation doped AlGaAs/GaAs/AlGaAs single quantum wells. Second, our experiments were carried out at 4.2 K and not in a mK regime. For this reason, the electron mobility in our samples was of the order of 6 × 10 5 cm 2 /Vs and not 10 7 cm 2 /Vs. This clearly indicates that the conditions of our measurements did not correspond to that of the well developed MIRO. Third, we explored both the low (120-660 GHz) and high (1.5-2.5 THz) frequency bands, which essentially enlarges the frequency range used previously, and...

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Photoresponse of a two-dimensional electron gas at the second harmonic of the cyclotron resonance

et al. 2015

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“…A more detailed account on magnetospectroscopy studies carried out on samples processed on this heterostructure is given in. 4,5 The measurements were carried out at 4 K by placing the sample in a center of a superconducting coil. The sample was cooled by an exchange He gas.…”

Section: Samples and Experimentsmentioning

confidence: 99%

Visible-light controlled plasma excitations in high electron mobility GaAs/AlGaAs heterostructure

et al. 2014

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Terahertz detectors based on GaAs/AlGaAs heterostructure were investigated at low temperatures and high magnetic fields. A response of detectors showed a line caused by a cyclotron resonance transition which was accompanied by several peaks originated form excitation of magnetopasmons. Illumination with a visible light caused an increase of the plasma concentration and resulted in a change of the magnetoplasmon spectrum. An analysis of spectra allowed to determine changes in the plasmon dispersion relation with a visible light which gives a tool to tune a THz response of a plasmonic detector.

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“…First, there have been an interest in basic studies of low-energy excitations of a 2DEG, particularly at very low temperatures and high magnetic fields [2,3]. Second, such structures exhibit two types of excitations, i.e., a cyclotron resonance (CR) and a magnetoplasmons (MPs), which can serve as a basis for construction of magnetic-field tunable resonant detectors [4].…”

Section: Introductionmentioning

confidence: 99%

“…The semiconductor system most often used for studies of the CR and MPs is a modulation doped GaAs/AlGaAs heterostructure or a quantum well because of a high mobility of electrons. However, recently we have shown [1,4,6,7] that magnetoplasmon spectroscopy at THz frequencies can be carried out also on † We consider here the case the most frequently realized in experiments, when k is high enough so that the group velocity of plasmon is smaller than the phase velocity of light propagating in the medium. This non-retarded limit can change to a retarded one if k is very small or the characteristic dimensions of the sample big enough.…”

Section: Introductionmentioning

confidence: 99%

Terahertz Spectroscopy of Double CdTe/CdMgTe Quantum Wells

et al. 2019

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Modulation doped CdTe/CdMgTe double quantum wells were studied at low temperatures and high magnetic fields. Transmission of THz monochromatic radiation from a molecular laser was studied as a function of magnetic field on samples with a grid processed on the surface either by evaporation of metallic stripes or by etching stripe-like trenches which cut only the well positioned closer to the surface. We compare dispersion relations of THz excitations in these samples and in an unprocessed one and we show that the strength of magnetoplasmon excitations in samples studied can be considered as a promising basis to construct magnetic-field tunable THz detectors.

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Plasmon dispersions in high electron mobility terahertz detectors

Cited by 22 publications

References 29 publications

Photoresponse of a two-dimensional electron gas at the second harmonic of the cyclotron resonance

Photoresponse of a two-dimensional electron gas at the second harmonic of the cyclotron resonance

Visible-light controlled plasma excitations in high electron mobility GaAs/AlGaAs heterostructure

Terahertz Spectroscopy of Double CdTe/CdMgTe Quantum Wells

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