Coherent magnetotransport and time-dependent transport through split-gated quantum constrictions

Torfason, Kristinn; Tang, Chi-Shung; Guðmundsson, Viðar

doi:10.1103/physrevb.80.195322

Cited by 4 publications

(3 citation statements)

References 45 publications

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“…During the past decade there has been increasing interest in exploring time-dependent quantum transport through open mesoscopic systems in a strong systemlead coupling regime. [1][2][3][4][5][6][7] Utilizing the tunable dynamic response of transient time-dependent transport enables development of switchable mesoscale electronic devices, in which the interplay of the mesoscopic system with external perturbations plays an important role. [8][9][10][11][12] In the weak system-lead coupling regime, the wideband and the Markovian approximation are usually employed, by neglecting the energy dependence of the electron tunneling rate, as well as memory effects in the system, respectively.…”

Section: Introductionmentioning

confidence: 99%

Time-dependent transport of electrons through a photon cavity

et al. 2012

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We use a non-Markovian master equation to describe the transport of Coulomb interacting electrons through an electromagnetic cavity with one quantized photon mode. The central system is a finite parabolic quantum wire that is coupled weakly to external parabolic quasi-one-dimensional leads at $t=0$. With a stepwise introduction of complexity to the description of the system and a corresponding stepwise truncation of the ensuing many-body spaces we are able to describe the time-dependent transport of Coulomb-interacting electrons through a geometrically complex central system. We take into account the full electromagnetic interaction of electrons and cavity photons without resorting to the rotating wave approximation or reduction of the electron states to two levels. We observe that the number of initial cavity photons and their polarization can have important effects on the transport properties of the system. The quasiparticles formed in the central system have a lifetime limited by the coupling to the leads and radiation processes active on a much longer timescale.Comment: RevTeX (pdf-LaTeX) 11 pages with 12 jpg-figures include

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Section: Introductionmentioning

confidence: 99%

Time-dependent transport of electrons through a photon cavity

et al. 2012

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“…These limits are the interest for our work. The manipulation of the quantum point contact [24,25] (QPC) connector width w can induce different transport regimes in these systems [26,27], e.g. at small w values we observe Coulomb blockade peaks in the conductance, for intermediate values we arrive at the Kondo transport regime and, finally, for high values Fano resonances are found.…”

Section: Introductionmentioning

confidence: 99%

Magneto-conductance fingerprints of purely quantum states in the open quantum dot limit

Mendoza

Ujevic

2012

J. Phys.: Condens. Matter

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We present quantum magneto-conductance simulations, at the quantum low energy condition, to study the open quantum dot limit. The longitudinal conductance G(E,B) of spinless and non-interacting electrons is mapped as a function of the magnetic field B and the energy E of the electrons. The quantum dot linked to the semi-infinite leads is tuned by quantum point contacts of variable width w. We analyze the transition from a quantum wire to an open quantum dot and then to an effective closed system. The transition, as a function of w, occurs in the following sequence: evolution of quasi-Landau levels to Fano resonances and quasi-bound states between the quasi-Landau levels, followed by the formation of crossings that evolve to anti-crossings inside the quasi-Landau level region. After that, Fano resonances are created between the quasi-Landau states with the final generation of resonant tunneling peaks. By comparing the G(E,B) maps, we identify the closed and open-like limits of the system as a function of the applied magnetic field. These results were used to build quantum openness diagrams G(w,B). Also, these maps allow us to determine the w-limit value from which we can qualitatively relate the closed system properties to the open one. The above analysis can be used to identify single spinless particle effects in experimental measurements of the open quantum dot limit.

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“…As examples, we can mention the quantum Hall effect 1,2 and the conductance quantization. 3,4 To understand the mechanics of quantum interference that controls these effects as a function of the magnetic field, 5,6 the use of electrostatic confinement through metallics gates 7 devices as quantum wire 8,9 ͑QW͒, quantum point contacts 10,11 ͑QPCs͒, and open quantum dots 12,13 ͑OQDs͒ are adequate. In this context, the combination of electrostatic and magnetic confinement results in an elegant and useful form to manipulate the quantum interference of the electronic states.…”

Section: Introductionmentioning

confidence: 99%

Fingerprints of transverse and longitudinal coupling between induced open quantum dots in the longitudinal magnetoconductance through antidot lattices

Ujevic

Mendoza

2010

Phys. Rev. B

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We propose numerical simulations of longitudinal magnetoconductance through a finite antidot lattice located inside an open quantum dot with a magnetic field applied perpendicular to the plane. The system is connected to reservoirs using quantum point contacts. We discuss the relationship between the longitudinal magnetoconductance and the generation of transversal couplings between the induced open quantum dots in the system. The system presents longitudinal magnetoconductance maps with crossovers ͑between transversal bands͒ and closings ͑longitudinal decoupling͒ of fundamental quantum states related to the open quantum dots induced by the antidot lattice. A relationship is observed between the distribution of antidots and the formed conductance bands, allowing a systematic follow up of the bands as a function of the applied magnetic field and quantum point-contact width. We observed a high conductance intensity ͓between n and ͑n +1͒ quantum of conductance, n =1,2,. . .͔ in the regions of crossover and closing of states. This suggests transversal couplings between the induced open quantum dots of the system that can be modulated by varying both the antidots potential and the quantum point-contact width. A new continuous channel ͑not expected͒ is induced by the variation in the contact width and generate Fano resonances in the conductance. These resonances can be manipulated by the applied magnetic field.

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Coherent magnetotransport and time-dependent transport through split-gated quantum constrictions

Cited by 4 publications

References 45 publications

Time-dependent transport of electrons through a photon cavity

Time-dependent transport of electrons through a photon cavity

Magneto-conductance fingerprints of purely quantum states in the open quantum dot limit

Fingerprints of transverse and longitudinal coupling between induced open quantum dots in the longitudinal magnetoconductance through antidot lattices

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