Control of the dipole domain propagation in a GaAs/AlAs superlattice with a high-frequency field

Schomburg, E.; Hofbeck, K.; Scheuerer, R.; Haeussler, Mathias; Renk, K. F.; Jappsen, A.-K.; Amann, Andreas; Wacker, Andreas; Schöll, Eckehard; Pavel'ev, D.G.; Koschurinov, Yu.

doi:10.1103/physrevb.65.155320

Cited by 21 publications

(10 citation statements)

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“…For a reliable operation of a superlattice as an ultra-high frequency oscillator such unpredictable and irregular conditions should be avoided. In principle, synchronization of oscillations in a superlattice by an external signal [17] could be exploited to achieve a desired periodic behavior. However, in reality, the control of the forcing frequency in the ultrahigh range presents substantial technical problems.…”

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confidence: 99%

Self-stabilization of high-frequency oscillations in semiconductor superlattices by time-delay autosynchronization

et al. 2003

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We present a scheme to stabilize high-frequency domain oscillations in semiconductor superlattices by a time-delayed feedback loop. Applying concepts from chaos control theory we propose to control the spatiotemporal dynamics of fronts of accumulation and depletion layers which are generated at the emitter and may collide and annihilate during their transit, and thereby suppress chaos. The proposed method only requires the feedback of internal global electrical variables, viz., current and voltage, which makes the practical implementation very easy.

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Self-stabilization of high-frequency oscillations in semiconductor superlattices by time-delay autosynchronization

et al. 2003

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“…A more detailed examination indicates that the local minima in IZI correspond to the locking regions marked by v1/v, and q5 increases with v1 in those intervals, while a decrease is frequently observed outside these ranges where quasi-periodic or possibly chaotic behavior occurs. Thus the presence of several locking intervals [11] explains the variety of peaks.…”

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confidence: 97%

<title>Synchronization of dipole domains in GHz-driven superlattices</title>

et al. 2002

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We consider a semiconductor superlattice biased into the regime of negative differential conductivity and driven by an additional GHz ac voltage, and find frequency-locked or quasiperiodic propagating field domains. With increasing driving frequency, the complex impedance exhibits strong variations of its amplitude and phase. An anomalous phase shift appears as a result of phase synchronization of the traveling domains.As predicted by Esaki and Tsu [1], semiconductor superlattices show pronounced negative differential conductivity (NDC). If the total bias is chosen such that the average electric field is in the NDC region, stable inhomogeneous field distributions (field domains) [2] or self-sustained oscillations [3] with frequencies up to 150 GHz at room temperature [4] appear. Which of these scenarios occurs depends on bias, doping, temperature, and the properties of the injecting contact [5]. For a more detailed discussion see Refs. [6,7].

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“…A more detailed examination indicates that the local minima in |Z| correspond to the locking regions, and φ increases with ν 1 in those intervals, while a decrease is frequently ob-served outside these ranges where quasi-periodic or possibly chaotic behavior occurs. Thus the presence of several locking intervals 16 explains the variety of peaks. For high frequencies ν 1 ≫ ν 0 the variations of Z become less pronounced and |Z| ∼ 300Ω and φ ≈ −π/2 is observed.…”

Section: High-frequency Impedance Of Driven Superlatticesmentioning

confidence: 97%

High-frequency impedance of driven superlattices

Jappsen

Amann

Wacker

et al. 2002

Journal of Applied Physics

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The complex impedance of a semiconductor superlattice biased into the regime of negative differential conductivity and driven by an additional GHz ac voltage is computed. From a simulation of the nonlinear spatio-temporal dynamics of traveling field domains we obtain strong variations of the amplitude and phase of the impedance with increasing driving frequency. These serve as fingerprints of the underlying quasiperiodic or frequency locking behavior. An anomalous phase shift appears as a result of phase synchronization of the traveling domains. If the imaginary part of the impedance is compensated by an external inductor, both the frequency and the intensity of the oscillations strongly increase. 72.20.Ht, Semiconductor superlattices (SL) show pronounced negative differential conductivity (NDC)1 . If the total bias is chosen such that the average electric field is in the NDC region, stable inhomogeneous field distributions (field domains) 2 or self-sustained oscillations 3 with frequencies up to 150 GHz at room temperature 4 appear. Which of these scenarios occurs depends on bias, doping, temperature, and the properties of the injecting contact [5][6][7][8][9][10] . For a recent overview see Ref.11 . In order to apply the self-sustained oscillations as a high-frequency generator in an electronic device, it is crucial to know the response of the SL in an external circuit. A key ingredient for the analysis is the complex impedance of the SL in the respective frequency range. This is the subject of this paper where the complex impedance is evaluated numerically by imposing an additional ac bias to the SL. The interplay of the selfsustained oscillations and the external frequency causes a variety of interesting phenomena such as frequency locking, quasi-periodic and chaotic behavior which has been extensively studied both theoretically 12-14 and experimentally 15,16 . In contrast to those studies we focus on the response to the circuit and concurrent phase synchronization phenomena in this work.We describe the dynamical evolution of the SL by rate equations for the electron densities in the quantum wells, together with Poisson's equation for the electric fields. The current densities J j→j+1 between adjacent quantum wells are evaluated within the model of sequential tunneling, and Ohmic boundary conditions with a contact conductivity σ are used. For details see Refs.10,11 . Here we apply a periodic bias signal U (t) = U dc + U ac sin(2πν 1 t) and study the total current I(t) = A N j=0 J j→j+1 /(N + 1). In particular we consider the Fourier component I ac (ν 1 ) sin(2πν 1 t − φ) which gives the complex impedanceAs an example we consider the SL structure studied in Ref.16 . It consists of N = 120 GaAs wells of width 4.9 nm separated by 1.3 nm AlAs barriers. The sample is n-doped with a density of 8.7 × 10 10 cm −2 per period and the sample cross section is A = 64 (µm) 2 . We estimate the energy broadening Γ = 15 meV, which effectively gives the sum of phonon, impurity and interface roughness scattering rates. All cal...

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Control of the dipole domain propagation in a GaAs/AlAs superlattice with a high-frequency field

Cited by 21 publications

References 27 publications

Self-stabilization of high-frequency oscillations in semiconductor superlattices by time-delay autosynchronization

Self-stabilization of high-frequency oscillations in semiconductor superlattices by time-delay autosynchronization

<title>Synchronization of dipole domains in GHz-driven superlattices</title>

High-frequency impedance of driven superlattices

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