Electron waveguide devices

Alamo, J.A. del; Eugster, Cristopher C.; Hu, Qichao; Melloch, M. R.; Rooks, M. J.

doi:10.1006/spmi.1996.0429

Cited by 18 publications

(17 citation statements)

References 20 publications

(31 reference statements)

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“…Recent experiments show that the transport characteristics are masked by the bolometric effect when the entire QPC, including the end-electrodes, is exposed to the incident electromagnetic field. 20 Second, the length L of the time-dependent field has to be shorter than the wave length of the incident field. The purpose is to increase the coupling between the electrons and the photons by breaking the longitudinal translational invariance.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

“…More recently, attentions have been shifted to QPC's acted upon by high frequency fields. These time-dependent fields include transversely, 15,16,17,18,19,20,21,22,23,24,25,26,27,28 or longitudinally 29,30 polarized fields, or simply gate-induced time-modulated potentials. 33,34,35 These studies focus on coherent inelastic scatterings by assuming the range of the time-modulated fields to be shorter than the incoherent mean free path.…”

Section: Introductionmentioning

confidence: 99%

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Coherent quantum transport in the presence of a finite-range transversely polarized time-dependent field

Tang

Chu

2000

Physica B: Condensed Matter

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This work investigates the quantum transport in a narrow constriction acted upon by a finiterange transversely polarized time-dependent electric field. A generalized scattering-matrix method is developed that has incorporated a time-dependent mode-matching scheme. The transverse field induces coherent inelastic scatterings that include both intersubband and intersideband transitions. These scatterings give rise to the dc conductance G a general suppressed feature that escalates with the chemical potential. In addition, particular suppressed features -the dip structures -are found in G. These features are recognized as the quasi-bound-state (QBS) features that arise from electrons making intersubband transitions to the vicinity of a subband bottom. For the case of larger field intensities, the QBS features that involve more photons are more evident. These QBS features are closely associated with the singular density of states at the subband bottoms. An experimental setup is proposed for the observation of these features.

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Section: Numerical Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Coherent quantum transport in the presence of a finite-range transversely polarized time-dependent field

Tang

Chu

2000

Physica B: Condensed Matter

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“…5) is analogous to the role of the thin depleting middle gate in the tunnel-barrier split electron waveguides. 16 The middlegate architecture [16][17][18][19] has been designed for fabrication of DQWrs by tunnel-barrier splitting of an ordinary wide QWr in two. An extremely narrow gate, manufactured with the help of the direct-write electron-beam lithography, 16,19 provides such a splitting.…”

Section: ͑42͒mentioning

confidence: 99%

“…16 The middlegate architecture [16][17][18][19] has been designed for fabrication of DQWrs by tunnel-barrier splitting of an ordinary wide QWr in two. An extremely narrow gate, manufactured with the help of the direct-write electron-beam lithography, 16,19 provides such a splitting. The obtained DQWrs (split electron waveguides) with autonomously contacted halves have been intended for implementation of ballistic resonant tunnel couplers 20,21 and other resonant devices.…”

Section: ͑42͒mentioning

confidence: 99%

Quantum wires and dots induced in a semiconductor by charged metallic filaments separated by an isolating barrier

Gribnikov

Haddad

2005

Journal of Applied Physics

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A very thin positively charged metallic filament separated from a surface of a semiconductor ͑S͒ by a thin nontunneling potential barrier ͑B͒ induces a quantum wire (QWr) in the semiconductor at the B / S interface. Single-electron quantum states of this QWr are controlled by a potential (and a charge) of the metallic filament. Two close parallel metallic filaments placed over such a B / S interface form a double-quantum wire with the ground and the first excited electron states, which appear as a result of a symmetric-antisymmetric splitting of the ground electron state in the single QWr. Two crossed metallic filaments, which are parallel to the B / S interface, form a quantum dot with completely localized electron states under the crossing point of the metallic filaments. The analogous crossing of a metallic filament by a pair of close metallic filaments forms a double-quantum dot (DQD). The latter can serve as a two-level qubit cell. Such qubits can be controlled by potentials of three independent metallic filaments inducing the above-mentioned DQD. Besides this "outside" metallic wire control, the DQDs can be connected to each other across the "inside" quantum wires, which have formed these DQDs by crossing.

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“…Recent experiments show that the transport characteristics are masked by the bolometric effect when the entire QPC, including the end-electrodes, is exposed to the incident electromagnetic field. 34 Second, in the above numerical examples, the length L of the region acted upon by the electromagnetic field is shorter than the wavelength of the incident field. The purpose is to increase the coupling between the electrons and the photons by breaking the longitudinal translational invariance.…”

mentioning

confidence: 98%

Coherent quantum transport in narrow constrictions in the presence of a finite-range longitudinally polarized time-dependent field

Tang

Chu

1999

Phys. Rev. B

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We have studied the quantum transport in a narrow constriction acted upon by a finite-range longitudinally polarized time-dependent electric field. The electric field induces coherent inelastic scatterings which involve both intra-subband and inter-sideband transitions. Subsequently, the dc conductance G is found to exhibit suppressed features. These features are recognized as the quasibound-state (QBS) features which are associated with electrons making transitions to the vicinity of a subband bottom, of which the density of states is singular. Having valley-like instead of dip-like structures, these QBS features are different from the G characteristics for constrictions acted upon by a finite-range time-modulated potential. In addition, the subband bottoms in the time-dependent electric field region are shifted upward by an energy proportional to the square of the electric field and inversely proportional to the square of the frequency. This effective potential barrier is originated from the square of the vector potential and it leads to the interesting field-sensitive QBS features. An experimental set-up is proposed for the observation of these features.

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Electron waveguide devices

Cited by 18 publications

References 20 publications

Coherent quantum transport in the presence of a finite-range transversely polarized time-dependent field

Coherent quantum transport in the presence of a finite-range transversely polarized time-dependent field

Quantum wires and dots induced in a semiconductor by charged metallic filaments separated by an isolating barrier

Coherent quantum transport in narrow constrictions in the presence of a finite-range longitudinally polarized time-dependent field

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