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Murdin, Ben; Heiß, Wolfgang; Langerak, C.J.G.M.; Lee, S C; Galbraith, I.; Strasser, G.; Gornik, E.; Helm, M.; Pidgeon, C. R.

doi:10.1103/physrevb.55.5171

Cited by 131 publications

(49 citation statements)

References 25 publications

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“…23 The existence of a bottleneck in the cooling of carriers between subbands in wide quantum wells when the subband separation is smaller than the LO phonon energy has been observed previously. 24 Lifetimes of the order of 50 ps due to acoustic phonon emission were found at low temperatures. In this system ͑with zero magnetic field͒ there are always states that exist at the phonon energy but away from the subband minimum, and thus the bottleneck may be overcome by increasing the temperature above some activation threshold, 35 K in that case.…”

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confidence: 99%

Suppression of LO phonon scattering in Landau quantized quantum dots

et al. 1999

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Picosecond time-resolved far-infrared measurements are presented of the scattering between conductionband states in a doped quasi quantum dot. These states are created by the application of a magnetic field along the growth direction of an InAs/AlSb quantum well. A clear suppression of the cooling rate is seen, from 10 12 s Ϫ1 when the level spacing is equal to the phonon energy, to 10 10 s Ϫ1 away from this resonance, and thus the results provide unambiguous evidence for the phonon bottleneck. Furthermore, the lifetimes had only weak dependence on temperature between 4 and 80 K. ͓S0163-1829͑99͒50612-7͔Electronic lifetimes of two-dimensional ͑2D͒ systems in magnetic fields are of fundamental interest in part because the quantization effect of the magnetic field mimics the effect of a quantum dot potential with an easily variable degree of confinement. 1 The magnetic field perpendicular to the layers forces the electrons into confined orbits and the density of states becomes a ladder of broadened ␦ functions similar to that of a quantum dot. Recently much work has been carried out on the so-called ''phonon bottleneck'' that has been claimed to inhibit the cooling of carriers in quantum dots when the level separation is not equal to the phonon energy. [2][3][4][5][6] However, partly as a result of different groups using different growth techniques for interband photoluminescence samples and partly on fundamental grounds, this is controversial and is the subject of much debate. 7-12 Indeed several mechanisms have been proposed that may bypass the bottleneck, such as multiphonon scattering, 7 Auger processes, 8 excitonic effects, 9 and defect related processes. 10 In the present work we observe clear phonon suppression in n-type quasi 0D dots ͑i.e., Landau quantized rather than spatially quantized͒ by a time-resolved intraband absorption measurement. This provides unambiguous evidence for the phonon bottleneck effect independently of arguments concerning which processes dominate in the interband photoluminescence measurements in dots 3-6,9-12 and quasi dots 13 such as electron-hole scattering. Further, because of the very clean model system ͑much sharper interfaces and no wetting layer, etc.͒, the interpretation is not complicated by detailed questions about different growth techniques and the quality of different dot sample structures. The results should assist in the understanding of which aspect of these processes is fundamental and which is dependent on sample structure.Resonant absorption of longitudinal optic ͑LO͒ phonons causes a variety of transport properties to oscillate with applied magnetic field, such as the magnetoresistance. 14 Resonant phonon scattering occurs whenwhere ប LO is the LO phonon energy, ប c ϭបeB/m* is the cyclotron energy, and ⌬l is an integer. At these resonances the LO phonon absorption/emission probability is strongly enhanced giving rise to large changes in the electron energy relaxation lifetime. 15,16 In the present work we have used the pump-probe technique, with cyclotron resonan...

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Suppression of LO phonon scattering in Landau quantized quantum dots

et al. 1999

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“…6,[13][14][15] When a GaAs-based electron gas is subjected to a quantizing magnetic field and a laser field with a frequency f ϳ1 THz and an intensity F 0 ϳ10 kV/cm ͑or output power Iϳ100 kW/cm 2 ͒, 6 conditions such as ϳ LO ϳ c and r 0 qϳ1 can be satisfied. As a consequence, the photon-modified MPR effect can be observed and the effects caused by magnetophoton-phonon coupling can be examined.…”

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Terahertz-photon-modified magnetotransport in a semiconductor in Voigt geometry

Khmyrova

Ryzhii

2001

Phys. Rev. B

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We present a theoretical study of transport and optical properties of a semiconductor-based electron gas subjected simultaneously to quantizing magnetic fields and intense terahertz ͑THz͒ laser fields in Voigt geometry. It is found that the presence of the THz radiation can result in an enhanced magnetophonon resonance effect and a resonant-absorption peak can be observed at about f ϳ1 THz for GaAs in high magnetic fields. The results are pertinent to experiments where THz free-electron lasers are employed as intense radiation sources.

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“…[3][4][5][6][7][8][9][10] Terahertz lasers have been applied to the experimental investigation of nonlinear transport and optical properties in electron gases such as low-dimensional semiconductor systems. Many interesting terahertz phenomena have been investigated, including resonant absorption, 3 photon enhanced hot-electron effect, 6 terahertz photon-induced impact ionization, 7 LO-phonon bottleneck effect, 8 terahertz photon assisted tunneling, 9 terahertz cyclotron resonance, 10 terahertz switching effects in tunneling diodes. [11][12][13] The conductivity changes due to an ac field radiation were calculated using a perturbative method.…”

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Frequency-dependent electrical transport under intense terahertz radiation

Zhang

2002

Phys. Rev. B

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Direct observation of the LO phonon bottleneck in wide GaAs/AlxGa1

Cited by 131 publications

References 25 publications

Suppression of LO phonon scattering in Landau quantized quantum dots

Suppression of LO phonon scattering in Landau quantized quantum dots

Terahertz-photon-modified magnetotransport in a semiconductor in Voigt geometry

Frequency-dependent electrical transport under intense terahertz radiation

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