Gunn oscillations up to 20 GHz optically induced in GaAs/AlAs superlattice

Person, H. Le; Minot, C.; Boni, Leonardo De; Palmier, J.F.

doi:10.1063/1.106984

Cited by 45 publications

(22 citation statements)

References 11 publications

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“…The alternative is to start from the miniband model. Such calculations have been performed in [209,210] using the drift velocity from the relaxation time model. A more microscopic approach can be performed within the hydrodynamic model [167,211].…”

Section: Discussionmentioning

confidence: 99%

Semiconductor superlattices: a model system for nonlinear transport

2002

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Electric transport in semiconductor superlattices is dominated by pronounced negative differential conductivity. In this report the standard transport theories for superlattices, i.e. miniband conduction, Wannier-Stark-hopping, and sequential tunneling, are reviewed in detail. Their relation to each other is clarified by a comparison with a quantum transport model based on nonequilibrium Green functions. It is demonstrated how the occurrence of negative differential conductivity causes inhomogeneous electric field distributions, yielding either a characteristic sawtooth shape of the current-voltage characteristic or self-sustained current oscillations. An additional ac-voltage in the THz range is included in the theory as well. The results display absolute negative conductance, photon-assisted tunneling, the possibility of gain, and a negative tunneling capacitance. 2 Notation and list of symbolsThroughout this work we consider a superlattice, which is grown in the z direction. Vectors within the (x, y) plane parallel to the interfaces are denoted by bold face letters k, r, while vectors in 3 dimensional space are r, k, . . . . All sums and integrals extend from −∞ to ∞ if not stated otherwise.The following relations are frequently used in this work and are given here for easy reference:

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Section: Discussionmentioning

confidence: 99%

Semiconductor superlattices: a model system for nonlinear transport

2002

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“…8,9 According to a discrete drift model, 5 the current oscillations are caused by a periodic motion of the domain wall over a few periods of the SL, 10 and this is confirmed by photoluminescence measurements. 8,9 Note that damped oscillations ͑with frequencies up to 20 GHz͒ have been observed experimentally by Le Person et al 11 in a photoexcited wide-miniband SL with strong interwell coupling. These oscillations have been interpreted in terms of dipole charge waves.…”

Section: Introductionmentioning

confidence: 99%

Chaotic dynamics of electric-field domains in periodically driven superlattices

1996

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Self-sustained time-dependent current oscillations under dc voltage bias have been observed in recent experiments on n-doped semiconductor superlattices with sequential resonant tunneling. The current oscillations are caused by the motion and recycling of the domain wall separating low-and high-electric-field regions of the superlattice, as the analysis of a discrete drift model shows and experimental evidence supports. Numerical simulation shows that different nonlinear dynamical regimes of the domain wall appear when an external microwave signal is superimposed on the dc bias and its driving frequency and driving amplitude vary. On the frequency-amplitude parameter plane, there are regions of entrainment and quasiperiodicity forming Arnol'd tongues. Chaos is demonstrated to appear at the boundaries of the tongues and in the regions where they overlap. Coexistence of up to four electric-field domains randomly nucleated in space is detected under ac ϩdc driving.

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“…[23][24][25]37 They are able to demonstrate negative differential conductance, 23,37 which induces new regimes of collective charge transport accompanied by rich instability phenomena. 5,6,[38][39][40][41][42] The collective dynamics of miniband electrons 6,25 can be described by the one-dimensional (1D) current continuity equation…”

Section: Model Of a Strongly Coupled Semiconductor Superlatticementioning

confidence: 99%