Multistability of the current-voltage characteristics in doped GaAs-AlAs superlattices

Kastrup, J.; Grahn, H. T.; Ploog, K.; Prengel, F.; Wacker, A.; Schöll, Eckehard

doi:10.1063/1.112850

Cited by 121 publications

(83 citation statements)

References 13 publications

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“…Steady state solutions in the NDC bias voltage region are in general multistable. We can obtain different solutions at a given bias voltage by evolving solutions following different histories, 21 for example by decreasing voltages from a high initial bias. For a given voltage different values of the current with different density and spin polarization profiles may be achieved.…”

Section: ∆ (Mev)mentioning

confidence: 99%

Field-domain spintronics in magnetic semiconductor multiple quantum wells

2001

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We develop a theory of non-linear growth direction transport in magnetically doped II-VI compound semiconductor multiple-quantum-well systems. We find that the formation of electric field domains can be controlled by manipulating the space dependence of the band electron spin-polarization, using its exchange coupling to local moments. We emphasize the importance of band electron spin relaxation in limiting the strength of these effects.72.25. Dc, 72.25.Mk, 73.21.Cd, 75.50.Pp

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Section: ∆ (Mev)mentioning

confidence: 99%

Field-domain spintronics in magnetic semiconductor multiple quantum wells

2001

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“…The phenomenon discussed above may be exploited for device applications like those suggested for optical systems [6]. More complex time-dependent features are expected in heterostructures with many resonances [9] or in superlattices [13].…”

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confidence: 99%

Nonlinear resonant tunneling in systems coupled to quantum reservoirs

Presilla

Sjöstrand

1997

Phys. Rev. B

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An adiabatic approximation in terms of instantaneous resonances is developed to study the steady-state and time-dependent transport of interacting electrons in biased resonant tunneling heterostructures. The resulting model consists of quantum reservoirs coupled to regions where the system is described by nonlinear ordinary differential equations and has a general conceptual interest. 73.40.Gk, 05.45.+b The mathematical method recently proposed in [1] provides a significant advance in the solution of timedependent scattering problems for Schrödinger equations with nonlinearities concentrated near the resonances of the corresponding potential. The method consists in the separation of the original system in two coupled subsystems through the splitting of the wavefunction in two components. In this way, we can separately study the simple problem of a reservoir-like subsystem having only extended states and couple its solution to the other subsystem having resonance states. The solution of this second problem is then simplified by an adiabatic approximation in terms of instantaneous resonances.The situation investigated in [1] depicts ballistic transport in a double barrier heterostructure, i.e., the scattering of a wave-packet on a double barrier potential. The nonlinearity, concentrated in the well between the barriers, is due to the interaction of the electrons represented by the wave-packet (mean-field). Here, we generalize the approach [1] to the case of biased heterostructures where a band of scattering states are to be considered. For these systems, hysteresis in the current-voltage characteristics has been observed [2] and recognized as a consequence of the mutual interaction of the electrons trapped in the resonance [2,3]. We show that the approach [1] allows us to quantitatively reproduce experimental results like [4] and predict new time-dependent properties. Although illustrated in the case of heterostructures, these results are very general and have applications in fields like the theory of electric systems [5] and nonlinear optics [6,7].Let us consider a heterostructure whose conduction band edge profile consists of two barriers of height V 0 located in [a, b] and [c, d] with a < b < c < d along the growth direction x. Translational invariance is assumed in the plane parallel to the junctions. Suppose that a bias energy ∆V is applied between the emitter (x < a) and collector (x > d) regions uniformly doped with net donor concentration n D . At thermal equilibrium with temperature T , transport is due to a band of scattering states with Fermi energy E F = (3π 2 n D ) 2/3 (we use everywhere effective atomic unitsh = 2m * = 1 and e 2 /ε = 2a −1 B , where m * is the electron effective mass, ε the dielectric constant and a B =h 2 ε/(m * e 2 ) the effective Bohr radius). Due to the translational invariance in the plane parallel to the junctions, the single-electron scattering state at energy E along the x direction is described by the one-dimensional Schrödinger equationwhere V cb (x) is the step-like c...

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“…The remarkable property of these superlattices is in the fact that, unlike the Esaki diodes, this negative differential resistance does not need any tunneling, rather it comes from the direct conduction of electrons. Nonetheless, significant difficulty in synthesizing atomically precise, eptiaxial heterostructures has made it very challenging to realize such superlattice structures [2][3][4][5][6][7][8] . Much work has been done on modeling graphene nanoribbon heterostructures and superlattices which could exhibit NDR [9][10][11][12][13][14][15] .…”

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confidence: 99%

Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field-Effect Transistors

Smith

Llinas

Bokor

et al. 2018

IEEE Electron Device Lett.

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Ballistic quantum transport calculations based on the non-equilbrium Green's function formalism show that field-effect transistor devices made from chevron-type graphene nanoribbons (CGNRs) could exhibit negative differential resistance with peak-to-valley ratios in excess of 4800 at room temperature as well as steepslope switching with 6 mV/decade subtheshold swing over five orders of magnitude and ON-currents of 88 µA µm −1 . This is enabled by the superlattice-like structure of these ribbons that have large periodic unit cells with regions of different effective bandgap, resulting in minibands and gaps in the density of states above the conduction band edge. The CGNR ribbon used in our proposed device has been previously fabricated with bottom-up chemical synthesis techniques and could be incorporated into an experimentally-realizable structure.In 1970, L.Esaki and R. Tsu predicted 1 that in an appropriately made superlattice, it should be possible to obtain very narrow width bands, which could then lead to negative differential resistance. The remarkable property of these superlattices is in the fact that, unlike the Esaki diodes, this negative differential resistance does not need any tunneling, rather it comes from the direct conduction of electrons. Nonetheless, significant difficulty in synthesizing atomically precise, eptiaxial heterostructures has made it very challenging to realize such superlattice structures 2-8 . Much work has been done on modeling graphene nanoribbon heterostructures and superlattices which could exhibit NDR 9-15 . Other work has been done on steep slope devices based on GNR and CNT heterojunctions 16,17 . Gnani et al. showed how superlattices could be used in a III-V nanowire FET to achieve steep slope behavior by using the superlattice gap to filter high energy electrons in the OFF state 18 . Here, we show that the recently synthesized chevron nanoribbons 19 provides a natural, monolithic material system where narrow-width energy bands and negative differential resistance (NDR) can be achieved. Our atomistic calculations predict that the NDR behavior should manifest at room temperature along with sub-thermal steepness (<60 mV/decade at room temperature). Such NDR behavior could lead to completely novel devices for next generation electronics.Unlike a graphene sheet, a narrow strip etched out of graphene, often called a graphene nanoribbon (GNR), can provide a sizeable bandgap. As a result, GNRs could lead to devices with good ON/OFF ratio at the nanoscale. However, a number of studies have also shown the deleterious effect of edge roughness on the device performance 20,21 . Recent breakthroughs in bottom-up chemical synthesis can produce GNRs with atomistically pristine edge states and overcome this shortcoming 19 . In fact, a recent experimental work demonstrated working transistors with 9-and 13-AGNRs made with these techniques 22 . The methods used to synthesize these ribbons can also be used to generate complex periodic structures beyond simply armchair and zigzag nanoribbon...

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Multistability of the current-voltage characteristics in doped GaAs-AlAs superlattices

Cited by 121 publications

References 13 publications

Field-domain spintronics in magnetic semiconductor multiple quantum wells

Field-domain spintronics in magnetic semiconductor multiple quantum wells

Nonlinear resonant tunneling in systems coupled to quantum reservoirs

Negative Differential Resistance and Steep Switching in Chevron Graphene Nanoribbon Field-Effect Transistors

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