Miniband transport in a two-dimensional superlattice

Kleinert, P.; Bryskin, V. V.

doi:10.1006/spmi.1997.0461

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…[252,253] for quantum box superlattices and in Ref. [254] for a superlattice formed by quantum wires. Self-sustained current oscillations: As discussed in section 5, traveling field domains cause self-generated current oscillations in superlattices.…”

Section: Discussionmentioning

confidence: 99%

Semiconductor superlattices: a model system for nonlinear transport

2002

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Electric transport in semiconductor superlattices is dominated by pronounced negative differential conductivity. In this report the standard transport theories for superlattices, i.e. miniband conduction, Wannier-Stark-hopping, and sequential tunneling, are reviewed in detail. Their relation to each other is clarified by a comparison with a quantum transport model based on nonequilibrium Green functions. It is demonstrated how the occurrence of negative differential conductivity causes inhomogeneous electric field distributions, yielding either a characteristic sawtooth shape of the current-voltage characteristic or self-sustained current oscillations. An additional ac-voltage in the THz range is included in the theory as well. The results display absolute negative conductance, photon-assisted tunneling, the possibility of gain, and a negative tunneling capacitance. 2 Notation and list of symbolsThroughout this work we consider a superlattice, which is grown in the z direction. Vectors within the (x, y) plane parallel to the interfaces are denoted by bold face letters k, r, while vectors in 3 dimensional space are r, k, . . . . All sums and integrals extend from −∞ to ∞ if not stated otherwise.The following relations are frequently used in this work and are given here for easy reference:

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Section: Discussionmentioning

confidence: 99%

Semiconductor superlattices: a model system for nonlinear transport

2002

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“…Finally, we stress that the main features in the charge and spin pumping currents predicted here do not depend on the specific properties of the leads. Thus they appear not only in the case of the simple-squared-lattice leads used in our model, but also in the case of the other types of leads, e.g., the two-dimensional superlattice 64,65 and graphene leads. This provides more choices for the experimental investigations.…”

Section: Summary and Discussionmentioning

confidence: 91%

Single-parameter quantum charge and spin pumping in armchair graphene nanoribbons

Zhou

2012

Phys. Rev. B

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We investigate quantum charge and spin pumping in armchair graphene nanoribbons under a single ac gate voltage connected with nonmagnetic/ferromagnetic leads via the nonequilibrium Green's function method. In the case of nonmagnetic leads, where only part of the nanoribbon is subject to an ac gate voltage to break the left-right spatial symmetry, we discover that peaks of the charge pumping current appear at the Fermi energies around the sub-band edges in the ac-field-free region of the nanoribbon. In the case of ferromagnetic leads with the lead magnetizations being antiparallel to break the left-right symmetry, similar peaks appear in the spin pumping current when the Fermi energies are around the edges of the the majority-spin sub-bands in the ferromagnetic leads. All these peaks originate from the pronounced symmetry breaking in the transmissions with energies being around the corresponding sub-band edges. Moreover, we predict a pure spin current in the case of ferromagnetic leads with the whole graphene nanoribbon under an ac gate voltage. The ac-field-strength and ac-field-frequency dependencies of the pumping current are also investigated with the underlying physics revealed.

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Transport in semiconductor superlattices in quantizing parallel electric and magnetic fields

Bryksin

Kleinert

1999

Physica B: Condensed Matter

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Miniband transport in a two-dimensional superlattice

Cited by 4 publications

References 7 publications

Semiconductor superlattices: a model system for nonlinear transport

Semiconductor superlattices: a model system for nonlinear transport

Single-parameter quantum charge and spin pumping in armchair graphene nanoribbons

Transport in semiconductor superlattices in quantizing parallel electric and magnetic fields

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