Microscopic model for sequential tunneling in semiconductor multiple quantum wells

Aguado, Ramón; Platero, Gloria; Moscoso, Miguel; Bonilla, L. L.

doi:10.1103/physrevb.55.r16053

Cited by 65 publications

(141 citation statements)

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“…The experimental I-V curves have been obtained by sweeping the DC bias only in one direction -i.e, by increasing the DC bias in between the emitter and the collector. Nonetheless, it is possible to use more complicated numerical techniques such as the numerical continuation method [15] in order to obtain all of the unstable and multistable regions. The multistable regions for the current could be observed in the experimental curves along up and down voltage sweeps.…”

Section: Fig 2 Differential Conductivity Versus Bias Voltage and Mamentioning

confidence: 99%

“…2). Our calculations have been performed by direct numerical integration of the dynamical system [15] in order to permit a direct comparison with the experiment [13]. The experimental I-V curves have been obtained by sweeping the DC bias only in one direction -i.e, by increasing the DC bias in between the emitter and the collector.…”

Section: Fig 2 Differential Conductivity Versus Bias Voltage and Mamentioning

confidence: 99%

“…Following Ref. [15] and considering the formation of Landau levels in the planes perpendicular to the transport, we obtain the following expressions for the tunneling currents:…”

mentioning

confidence: 99%

“…Relaxation in the planes perpendicular to the transport is considered imposing current conservation in the stationary limit. This condition determines the sequential current as well as the Fermi energies within each well {ǫ ωi } [14,15]. The electrons are described by a Fermi-Dirac distribution in each well, which implicitly assumes that some scattering mechanism thermalizes them towards a local equilibrium situation.…”

mentioning

confidence: 99%

“…[15]. These rate equations, which include all of the relevant dynamics of the selfconsistent problem, can be rewriten in terms of an Ampère's law that explicitly shows the time-dependent current consisting of a displacement current plus a tunneling term [15] …”

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confidence: 99%

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Magnetic field induced charge instabilities in weakly coupled superlattices

Aguado

Platero

1998

Physica B: Condensed Matter

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Using a time dependent selfconsistent model for vertical sequential tunneling, we study the appearance of charge instabilities that lead to the formation of electric field domains in a weakly coupled doped superlattice in the presence of high magnetic fields parallel to the transport direction. The interplay between the high non linearity of the system -coming from the Coulomb interaction-and the inter-Landau-level scattering at the domain walls (regions of charge accumulation inside the superlattice) gives rise to new unstable negative differential conductance regions and extra stable branches in the sawtooth-like I-V curves.PACS numbers: 73.40. Gk, 72.15.Gd Weakly coupled doped semiconductor superlattices are an example of non linear systems in which all intrinsic properties related to high non linearity such as multistability, spatio-temporal chaos, etc, can be externally modified : e.g. by the application of a bias voltage or by the variation of the doping densities in the wells or in the contacts. The strong non linear transport that results from the Coulomb interaction in these systems presents a rich variety of new physical phenomena: multistability and electric field domains formation [1-3], self sustained oscillations [4], bifurcation to chaos [5], etc. In particular, the current flowing through a weakly coupled doped semiconductor superlattice presents a complicated sawtooth structure with unstable regions of negative differential conductance and multistable regions. This structure of branches comes from the charge instabilities that appear due to the motion of the domain wall (acummulation layer) from one well to another. This motion, which is due to resonant tunneling between adjacent subbands, leads to the formation of electric field domains. In this Letter we study theoretically for the first time this phenomenon in the presence of high magnetic fields parallel to the transport direction. New physical questions that were not relevant in the absence of magnetic fields can be raised. In particular, what happens to the charge instabilities in the presence of the new energy scale in the problem,hω c ? Resonant tunneling through double barriers [6-10] and superlattices [11] in the presence of high magnetic fields has been widely studied. Also, dynamical instabilities and bifurcations to chaos induced by a magnetic field in a double barrier resonant tunneling diode have been recently predicted [12]. It is well known that the application of a magnetic field perpendicular to a two dimensional electron gas produces the formation of Landau levels. For ideal samples, the tunneling through the heterostructure conserves the Landau level index. However, due to interface roughness, impurity scattering, or phonon scattering, these conservation rules are relaxed and inter Landau level transitions take place [6][7][8][9][10]. Recent magnetotransport experiments on weakly coupled doped semiconductor superlattices performed by Schmidt et al. [13] show new unstable regions of negative differential conductance and e...

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Section: Fig 2 Differential Conductivity Versus Bias Voltage and Mamentioning

confidence: 99%

Section: Fig 2 Differential Conductivity Versus Bias Voltage and Mamentioning

confidence: 99%

“…Following Ref. [15] and considering the formation of Landau levels in the planes perpendicular to the transport, we obtain the following expressions for the tunneling currents:…”

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Magnetic field induced charge instabilities in weakly coupled superlattices

Aguado

Platero

1998

Physica B: Condensed Matter

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Electric Field Domain Formation and Multistability in Semiconductor Multiple Quantum Wells in the Presence of THz Radiation

Aguado

Platero

1997

phys. stat. sol. (a)

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We propose a self‐consistent microscopic model of vertical sequential tunneling through multiple quantum wells in the presence of THz radiation. The model considers the Coulomb interaction in a mean field approximation. We analyze the current density through a double quantum well and a superlattice and study the formation of electric field domains in the presence of THz radiation and the appearance of new multistability regions, both caused by the combined effect of the strong nonlinearity coming from the Coulomb interaction and the new photon‐assisted tunneling channels. We show how the electric field domains can be supported by the virtual photonic sidebands due to multiple photon emission and absorption.

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Nonlinear Dynamics in Semiconductor Superlattices

Bonilla

Teitsworth

2010

Nonlinear Wave Methods for Charge Transport

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Microscopic model for sequential tunneling in semiconductor multiple quantum wells

Cited by 65 publications

References 20 publications

Magnetic field induced charge instabilities in weakly coupled superlattices

Magnetic field induced charge instabilities in weakly coupled superlattices

Electric Field Domain Formation and Multistability in Semiconductor Multiple Quantum Wells in the Presence of THz Radiation

Nonlinear Dynamics in Semiconductor Superlattices

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