Effect of phase breaking on ac transport through a quantum dot dimer

Yeung, T. C. Au; Shangguan, W. Z.; Chen, Q.-H; Yu, Yabin; Kam, C. H.; Wong, Meng-Ee

doi:10.1103/physrevb.65.035306

Cited by 3 publications

(2 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ac quantum transport properties have also been investigated in the super-conducting hybrid system [35][36][37]. To examine the phase breaking effect, ac quantum transport with electron-phonon interaction has been studied by several groups [21,38,39]. For electron transport, current-conserving and gauge-invariant conditions are two fundamental requirements [10,11].…”

Section: Introductionmentioning

confidence: 99%

Current-conserving and gauge-invariant quantum ac transport theory in the presence of phonon

Zhan

Wei

et al. 2014

Phys. Rev. B

View full text Add to dashboard Cite

Using the nonequilibrium Green's function (NEGF) approach, we develop a microscopic ac transport theory in the presence of electron-phonon interaction. Taking into account the self-consistent Coulomb interaction, the displacement current is included. This ensures that our theory satisfies the current-conserving and gauge-invariant conditions. Importantly, the inclusion of self-consistent Coulomb interaction naturally connects the NEGF formalism to the density functional theory (DFT). This allows us to calculate the self-consistent Hamiltonian using DFT within the NEGF framework, which paves the way for first principles ac transport calculation of nanoelectronic devices in the presence of electron-phonon interaction. It is known that the inelastic electron tunneling spectroscopy (IETS) is a powerful tool in studying the inelastic dc quantum transport in molecular devices. The basic idea of IETS is to obtain the information of vibrational spectrum of molecular devices by measuring the second derivative of the dc current with respect to the bias voltage. In the ac transport, we find that the phonon spectrum and electron-phonon coupling strength can be obtained from the second derivative of the admittance with respect to the frequency which is the working principle of the inelastic electron admittance spectroscopy (IEAS). Hence we propose to use IEAS to probe the effect of the phonon in ac transport. As an example, dynamic conductance of a quantum dot is discussed in detail and the concept of IEAS is demonstrated.

show abstract

Section: Introductionmentioning

confidence: 99%

Current-conserving and gauge-invariant quantum ac transport theory in the presence of phonon

Zhan

Wei

et al. 2014

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…Alternating-current transport properties of mesoscopic conductor systems have attracted much research attention, both experimental [1][2][3] and theoretical [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. In recent years, many studies of quantum dot (QD) systems consisting of coupled dots have appeared in the literature [8][9][10][11][12][13][14][15][16][19][20][21][22][23][24][25]. Büttiker et al [9][10][11] have published much work discussing the ac response of mesoscopic systems.…”

Section: Introductionmentioning

confidence: 99%

Alternating-current response of one-dimensional quantum dot arrays

Yu¹,

Yeung²,

Shangguan³

et al. 2002

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

A general approach is presented for calculating the dynamic conductance of coupled quantum dot systems. To consider the long-range Coulomb interaction, we introduce the capacitances between the leads and dots, gate electrodes and dots, and dots and dots. The displacement currents are also taken into account. Our results fulfil charge and current conservation requirements, as well as current and charge response invariance under an overall potential shift. We apply our approach to a one-dimensional quantum dot array by use of the non-equilibrium Green function techniques. The numerical results are presented for a three-quantum-dot system. Three-peak resonant structure of the alternating-current conductance is observed at low temperature. The effect of the capacitance on the frequency-dependent conductance is obvious, but less so at low frequency. The low-frequency conductance shows either capacitive or inductive behaviour depending on the chemical potential of the electron reservoirs, but sufficiently large capacitances may change this situation.

show abstract

Admittance of a one-dimensional double-barrier resonant tunneling nanostructure

Shangguan

Yeung

et al. 2002

Phys. Rev. B

Self Cite

View full text Add to dashboard Cite

We study the dynamic response of a one-dimensional double-barrier nanostructure to an ac bias. Combining the Schro ¨dinger equation, Poisson equation and the scattering theory, we calculate the internal potential, charge density, and the ac conductance as well. The results show that the charge distribution is antisymmetric with respect to the center of the double barrier, and depends crucially on the relative position of the Fermi level to the resonant energies of the well. The diagonal emittance is found to have a similar dependence. It is negative ͑inductive behavior͒ when the Fermi energy is very close to the resonant energies, and it reaches the negative maximum at resonant energies, while it is always positive ͑capacitive behavior͒ when the Fermi energy is within the barrier depth and far from resonance, and develops two peaks closely on both sides of the inductive peak. This result is in agreement with that obtained from discrete model. In addition, we find that the capacitive peaks correspond to the maxima of charge-density fluctuation, and inductive peaks to zero charge-density distribution. Therefore, the sign and magnitude of emittance reflect how the charge piles up inside the device.

show abstract

Effect of phase breaking on ac transport through a quantum dot dimer

Cited by 3 publications

References 23 publications

Current-conserving and gauge-invariant quantum ac transport theory in the presence of phonon

Current-conserving and gauge-invariant quantum ac transport theory in the presence of phonon

Alternating-current response of one-dimensional quantum dot arrays

Admittance of a one-dimensional double-barrier resonant tunneling nanostructure

Contact Info

Product

Resources

About