Dynamic response of a quantum wire structure

Yu, Yabin; Yeung, T. C. Au; Shangguan, W. Z.

doi:10.1103/physrevb.66.235315

Cited by 89 publications

(185 citation statements)

References 26 publications

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“…When the Fermi level is right at the resonant energy, the behavior of this system is similar to the case of a quantum wire ͑QW͒ with contacts, and with one channel open. According to the previous work, 25 with the increasing Fermi level, a quasiplateau of capacitance would appear after one channel is open. Here, in our case, the resonant energy 1.805 is at the front part of the plateau, so the capacitance should be quite large.…”

Section: ͑17͒mentioning

confidence: 77%

Dynamic response of a double barrier system: The effect of contacts

Yeung

Shangguan

et al. 2003

Phys. Rev. B

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We study the dynamical response of a double-barrier conductor with two contacts to investigate the contact effect on ac conduction in the system. We have presented the calculation of various physical quantities such as the distributions of internal potential and charge density, capacitance and low-frequency ac conductance. We show that the characteristic potentials would tend to unity ͑zero͒ in the reservoirs. When the system is far away from resonance, the charge distribution exists only around the barrier regions as a response to the applied voltage, and hence the contacts almost have no effect on the results. In the case of small transmission probability, we find a considerable amount of charge distribution surrounding the double-barrier conductor. As for the resonant case or near the resonance, our results show that the charge distribution displays large fluctuations outside the conductor, but almost no charge distribution within the conductor. In this case, the effect of contacts on the charge and potential distributions is considerable. Moreover, we find that qualitatively the presence of contacts does not change the main features of the emittance without contacts. But the contact effect on the capacitance is significant when the chemical potential is very close to resonant energy: there is a sharp capacitance peak at resonance that does not exist in the case without contacts.

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Section: ͑17͒mentioning

confidence: 77%

Dynamic response of a double barrier system: The effect of contacts

Yeung

Shangguan

et al. 2003

Phys. Rev. B

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“…Therefore, the scattering of the contacts is important for the systems such as the perfect ballistic wire and resonant double barrier structure. 8 In contrast, if the Poisson equation is replaced with the neutral ͑or strongly screening͒ condition in the perfect ballistic wire, our theory will be reduced to the one developed by Blanter and co-workers 9 In terms of the set of eigenstates K ͑r͒, the Fermi field operator is…”

Section: ͑4͒mentioning

confidence: 97%

“…To recover the current conservation, the noninteracting ac conductance has to be "modified " to fit TFA interacting conductance. 7,8 In addition, in our theory, the invariance conditions under an overall shift of potential, i.e., ͚ ␤ G ␣␤ ͑͒ = 0 and ͚ ␤ ␤ ͑r , ͒ = 0, can follow from Eqs. ͑7͒, ͑14͒, and ͑18͒.…”

Section: A External and Interacting Conductances And Current Conservmentioning

confidence: 97%

“…In the previous work, the interacting current response and internal potential were determined by some experiential approaches 1 or by Thomas-Fermi approximation ͑TFA͒ in the low-frequency limit. [5][6][7][8] In Ref. 9, the potentials were calculated by using RPA only for the perfect ballistic wire systems.…”

Section: A External and Interacting Conductances And Current Conservmentioning

confidence: 99%

“…[1][2][3] The total ac conductance of interacting carriers can be determined self-consistently by some experiential approaches 1,4 or in the case of very low frequency. [5][6][7][8] Moreover, a self-consistent theory based on random phase approximation 9 ͑RPA͒, as well as a Luttinger liquid theory 10 were proposed for the ac conductance and potential of a perfect ballistic wire. Also, some general formulations [11][12][13] of linear current response have been presented for a given electric potential distribution.…”

Section: Introductionmentioning

confidence: 99%

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Self-consistent theory for dynamic responses of mesoscopic systems

Liu

Quan

et al. 2007

Phys. Rev. B

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A self-consistent theory is developed for dynamic responses of mesoscopic-structure systems. Within the framework of exact linear response theory, we derive a set of self-consistent equations, with which the dynamic current, charge and potential responses to time-dependent external fields can be determined self-consistently, without any requirement for additional experiential parameters. As a natural consequence, the conservation of charge and total current as well as the gauge invariance conditions are fulfilled in this self-consistent approach.

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Thermoballistic spin-polarized electron transport in paramagnetic semiconductors

Lipperheide¹,

Wille²

2009

Ann. Phys.

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Spin-polarized electron transport in diluted magnetic semiconductors (DMS) in the paramagnetic phase is described within the thermoballistic transport model. In this (semiclassical) model, the ballistic and diffusive transport mechanisms are unified in terms of a thermoballistic current in which electrons move ballistically across intervals enclosed between arbitrarily distributed points of local thermal equilibrium. The contribution of each interval to the current is governed by the momentum relaxation length. Spin relaxation is assumed to take place during the ballistic electron motion. In paramagnetic DMS exposed to an external magnetic field, the conduction band is spin-split due to the giant Zeeman effect. In order to deal with this situation, we extend our previous formulation of thermoballistic spin-polarized transport so as to take into account an arbitrary (position-dependent) spin splitting of the conduction band. The current and density spin polarizations as well as the magnetoresistance are each obtained as the sum of an equilibrium term determined by the spin-relaxed chemical potential, and an off-equilibrium contribution expressed in terms of a spin transport function that is related to the splitting of the spin-resolved chemical potentials. The procedures for the calculation of the spin-relaxed chemical potential and of the spin transport function are outlined. As an illustrative example, we apply the thermoballistic description to spin-polarized transport in DMS/NMS/DMS heterostructures formed of a nonmagnetic semiconducting sample (NMS) sandwiched between two DMS layers. We evaluate the current spin polarization and the magnetoresistance for this case and, in the limit of small momentum relaxation length, find our results to agree with those of the standard drift-diffusion approach to electron transport.

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Dynamic response of a quantum wire structure

Cited by 89 publications

References 26 publications

Dynamic response of a double barrier system: The effect of contacts

Dynamic response of a double barrier system: The effect of contacts

Self-consistent theory for dynamic responses of mesoscopic systems

Thermoballistic spin-polarized electron transport in paramagnetic semiconductors

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