Escape time model for the current self-oscillation frequencies. in weakly coupled semiconductor superlattices

Rogozia, M.; Grahn, H. T.

doi:10.1007/s003390100746

Cited by 3 publications

(6 citation statements)

References 3 publications

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“…About the discrepancy in the frequency scales, the only mechanism for electron transport included in the model is sequential resonant tunneling. This means that the current and the frequency are too small compared to experimental values as already reported in [40].…”

mentioning

confidence: 69%

Noise-enhanced spontaneous chaos in semiconductor superlattices at room temperature

Alvaro¹,

Carretero²,

Bonilla³

2014

EPL

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Physical systems exhibiting fast spontaneous chaotic oscillations are used to generate high-quality true random sequences in random number generators. The concept of using fast practical entropy sources to produce true random sequences is crucial to make storage and transfer of data more secure at very high speeds. While the first high-speed devices were chaotic semiconductor lasers, the discovery of spontaneous chaos in semiconductor superlattices at room temperature provides a valuable nanotechnology alternative. Spontaneous chaos was observed in 1996 experiments at temperatures below liquid nitrogen. Here we show spontaneous chaos at room temperature appears in idealized superlattices for voltage ranges where sharp transitions between different oscillation modes occur. Internal and external noises broaden these voltage ranges and enhance the sensitivity to initial conditions in the superlattice snail-shaped chaotic attractor thereby rendering spontaneous chaos more robust.

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mentioning

confidence: 69%

Noise-enhanced spontaneous chaos in semiconductor superlattices at room temperature

Alvaro¹,

Carretero²,

Bonilla³

2014

EPL

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“…The additional prefactor in equation ( 100) yields a more complicated field dependence in our formulae. Our drift velocity is also similar to the escape time formula used by Rogozia and Grahn [88] to give an estimation of the frequency of current self-oscillations, provided that more precise expressions for T i with different electron masses for the wells and barriers are used (cf section 5.2.2).…”

Section: Sls With Several Minibands and Sequential Resonant Tunnellingmentioning

confidence: 88%

“…To simplify matters, we can assume that the broadening functions do not depend on the lateral momentum. The result can be further simplified by noting that the lateral momentum is conserved according to equation (88) and that the integral over k ⊥ affects only the distribution functions. We obtain…”

Section: Sls With Several Minibands and Sequential Resonant Tunnellingmentioning

confidence: 99%

“…5.2.2. Weakly coupled superlattices.The measured frequencies of current self-oscillations for weakly coupled SLs investigated by Rogozia and Grahn[88] are summarized in the last column of table 5 for samples with different well, d W , and barrier, d B , widths. The table also includes the number of periods, N , the energy of the involved sub-or minibands, E ν , as well as their widths, ν , which have been calculated using the Kronig-Penney model.…”

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confidence: 99%

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Non-linear dynamics of semiconductor superlattices

2005

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In the last decade, non-linear dynamical transport in semiconductor superlattices (SLs) has witnessed significant progress in theoretical descriptions as well as in experimentally observed non-linear phenomena. However, until now, a clear distinction between non-linear transport in strongly and weakly coupled SLs was missing, although it is necessary to provide a detailed description of the observed phenomena. In this review, strongly coupled SLs are described by spatially continuous equations and display self-sustained current oscillations due to the periodic motion of a charge dipole as in the Gunn effect for bulk semiconductors. In contrast, weakly coupled SLs have to be described by spatially discrete equations. Therefore, weakly coupled SLs exhibit a more complex dynamical behaviour than strongly coupled ones, which includes the formation of stationary electric field domains, pinning or propagation of domain walls consisting of a charge monopole, switching between stationary domains, self-sustained current oscillations due to the recycling motion of a charge monopole and chaos. This review summarizes the existing theories and the experimentally observed non-linear phenomena for both types of semiconductor SLs.

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“…Our additional prefactor in equation (A.10) yields a more complicated field dependence in our formulae. Our drift velocity is also similar to the escape time formula used by Rogozia and Grahn to give an estimation of the frequency of current self-oscillations [66], provided more precise expressions for T i (with different electron masses at wells and barriers) are used.…”

Section: Final Remarksmentioning

confidence: 91%

Theory of nonlinear charge transport, wave propagation, and self-oscillations in semiconductor superlattices

Bonilla¹

2002

J. Phys.: Condens. Matter

141

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Nonlinear charge transport in semiconductor superlattices under strong electric fields parallel to the growth direction results in rich dynamical behaviour including the formation of electric field domains, pinning or propagation of domain walls, self-sustained oscillations of the current and chaos. Theories of these effects use reduced descriptions of transport in terms of average charge densities, electric fields, etc. This is simpler when the main transport mechanism is resonant tunnelling of electrons between adjacent wells followed by fast scattering between subbands. In this case, we will derive microscopically appropriate discrete models and boundary conditions. Their analyses reveal differences between low-field behaviour where domain walls may move oppositely or parallel to electrons, and high-field behaviour where they can only follow the electron flow. The dynamics is controlled by the amount of charge available in the superlattice and doping at the injecting contact. When the charge inside the wells becomes large, boundaries between electric field domains are pinned resulting in multistable stationary solutions. Lower charge inside the wells results in self-sustained oscillations of the current due to recycling and motion of domain walls, which are formed by charge monopoles (high contact doping) or dipoles (low contact doping). Besides explaining wave motion and subsequent current oscillations, we will show how the latter depend on such controlling parameters as voltage, doping, temperature, and photoexcitation.

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Escape time model for the current self-oscillation frequencies. in weakly coupled semiconductor superlattices

Cited by 3 publications

References 3 publications

Noise-enhanced spontaneous chaos in semiconductor superlattices at room temperature

Noise-enhanced spontaneous chaos in semiconductor superlattices at room temperature

Non-linear dynamics of semiconductor superlattices

Theory of nonlinear charge transport, wave propagation, and self-oscillations in semiconductor superlattices

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