External Noise Effects on the Electron Velocity Fluctuations in Semiconductors

Adorno, Dominique Persano; Pizzolato, Nicola; Spagnolo, Bernardo

doi:10.12693/aphyspola.113.985

Cited by 16 publications

(6 citation statements)

References 7 publications

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“…[21,22], a way to improve the ultra-fast magnetization dynamics of magnetic spin systems by including random fields has been discussed. Noise enhanced stability induced by a superimposed source of noise in the electron transport in GaAs crystals, subjected to periodic electric fields, has been found [23,24]. In semiconductor quantum wells and wires, Glazov et al have demonstrated that the randomness in spin-orbit coupling is inevitable and can be attributed to both the electron-electron dynamic collisions and the static fluctuations in the density of dopant ions [25,26].…”

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confidence: 99%

Enhancement of electron spin lifetime in GaAs crystals: The benefits of dichotomous noise

Spezia

Adorno

Pizzolato

et al. 2013

EPL

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The electron spin relaxation process in n-type GaAs crystals driven by a fluctuating electric field is investigated. Two different sources of fluctuations are considered: (i) a symmetric dichotomous noise and (ii) a Gaussian correlated noise. Monte Carlo numerical simulations show, in both cases, an enhancement of the spin relaxation time by increasing the amplitude of the external noise. Moreover, we find that the electron spin lifetime versus the noise correlation time: (i) increases up to a plateau in the case of dichotomous random fluctuations, and (ii) shows a nonmonotonic behaviour with a maximum in the case of bulks subjected to a Gaussian correlated noise.

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confidence: 99%

Enhancement of electron spin lifetime in GaAs crystals: The benefits of dichotomous noise

Spezia

Adorno

Pizzolato

et al. 2013

EPL

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“…In the last decade, however, increasing interest has been directed toward possible constructive aspects of noise in the dynamical response of nonlinear systems [8][9][10]. The effect of an external source of noise on electron transport in GaAs crystals in the presence of static and/or periodic electric fields has been studied [11][12][13][14]. Furthermore, theoretical works which discuss the way to improve the ultra-fast magnetization dynamics of magnetic spin systems by including random fields have been recently published [15][16][17].…”

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confidence: 99%

New insights into electron spin dynamics in the presence of correlated noise

Spezia

Adorno²,

Pizzolato

et al. 2011

J. Phys.: Condens. Matter

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The changes in the spin depolarization length in zinc-blende semiconductors when an external component of correlated noise is added to a static driving electric field are analyzed for different values of field strength, noise amplitude and correlation time. Electron dynamics is simulated by a Monte Carlo procedure which takes into account all the possible scattering phenomena of the hot electrons in the medium and includes the evolution of spin polarization. Spin depolarization is studied by examining the decay of the initial spin polarization of the conduction electrons through the D'yakonov-Perel process, the only relevant relaxation mechanism in III-V crystals. Our results show that, for electric field amplitudes lower than the Gunn field, the dephasing length shortens with increasing noise intensity. Moreover, a nonmonotonic behavior of spin depolarization length with the noise correlation time is found, characterized by a maximum variation for values of noise correlation time comparable with the dephasing time. Instead, in high field conditions, we find that, critically depending on the noise correlation time, external fluctuations can positively affect the relaxation length. The influence of the inclusion of the electron-electron scattering mechanism is also shown and discussed.

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“…This means that the total power spectrum of the intrinsic noise is dependent on both the amplitude and the frequency of the excitation signals [10]. In the wake of these results, we have found that the opportunity to suppress the diffusion noise in semiconductor bulk materials exists also under cyclostationary conditions, by adding a Gaussian fluctuating contribution to the driving electric field [11].…”

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confidence: 77%

The influence of noise on electron dynamics in semiconductors driven by a periodic electric field

2009

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Studies about the constructive aspects of noise and fluctuations in different non-linear systems have shown that the addition of external noise to systems with an intrinsic noise may result in a less noisy response. Recently, the possibility to reduce the diffusion noise in semiconductor bulk materials by adding a random fluctuating contribution to the driving static electric field has been tested. The present work extends the previous theories by considering the noise-induced effects on the electron transport dynamics in low-doped n-type GaAs samples driven by a high-frequency periodic electric field (cyclostationary conditions). By means of Monte Carlo simulations, we calculate the changes in the spectral density of the electron velocity fluctuations caused by the addition of an external correlated noise source. The results reported in this paper confirm that, under specific conditions, the presence of a fluctuating component added to an oscillating electric field can reduce the total noise power. Furthermore, we find a nonlinear behaviour of the spectral density with the noise intensity. Our study reveals that, critically depending on the external noise correlation time, the dynamical response of electrons driven by a periodic electric field receives a benefit by the constructive interplay between the fluctuating field and the intrinsic noise of the system.

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External Noise Effects on the Electron Velocity Fluctuations in Semiconductors

Cited by 16 publications

References 7 publications

Enhancement of electron spin lifetime in GaAs crystals: The benefits of dichotomous noise

Enhancement of electron spin lifetime in GaAs crystals: The benefits of dichotomous noise

New insights into electron spin dynamics in the presence of correlated noise

The influence of noise on electron dynamics in semiconductors driven by a periodic electric field

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