Fano regime of transport through open quantum dots

Racec, E. R.; Wulf, Ulrich; Racec, Paul N.

doi:10.1103/physrevb.82.085313

Cited by 17 publications

(28 citation statements)

References 44 publications

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“…We demonstrate the power of such a tool to contribute to a physical picture behind the Fano resonance in a relativistic stadium, corroborating the studies of Huang 10 and Racec 22 . It is our hope to use this tool to examine the mixing of reflected modes in weakly ergodic systems in future studies.…”

Section: Discussionsupporting

confidence: 66%

“…It has been suggested by Racec et al 22 that the asymmetry q-factor can be explained by the relative lateral symmetry between the direct and scattering states. In this case, we expect the asymmetric pattern in transmission to reverse, to reflect the fact that we are now reflecting off the same side of the system, as opposed to tunneling through it.…”

Section: Reflection Matrix For Single-lead Relativistic Stadiummentioning

confidence: 99%

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Algorithm for efficient elastic transport calculations for arbitrary device geometries

2011

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With the growth in interest in graphene, controlled nanoscale device geometries with complex form factors are now being studied and characterized. There is a growing need to understand new techniques to handle efficient electronic transport calculations for these systems. We present an algorithm that dramatically reduces the computational time required to find the local density of states and transmission matrix for open systems regardless of their topology or boundary conditions. We argue that the algorithm, which generalizes the recursive Green's Function method by incorporating the reverse Cuthill-McKee algorithm for connected graphs, is ideal for calculating transmission through devices with multiple leads of unknown orientation, and becomes a computational necessity when the input and output leads overlap in real space. This last scenario takes the Landauer-Buttiker formalism to general scattering theory in a computational framework that makes it tractable to perform full-spectrum calculations of the quantum scattering matrix in mesoscopic systems. We demonstrate the efficacy of these approaches on graphene stadiums, a system of recent scientific interest, and contribute to a physical understanding of Fano resonances which appear in these systems.

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Section: Discussionsupporting

confidence: 66%

Section: Reflection Matrix For Single-lead Relativistic Stadiummentioning

confidence: 99%

Algorithm for efficient elastic transport calculations for arbitrary device geometries

2011

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“…the CSN in contact with the external leads, we use the scattering formalism based on the R-matrix method. This method has been used in similar transport problems in quantum dots connected to the leads via quantum point contacts [25], in planar nanotransistors [26,27], or in cylindrical bulk nanowires with radial constrictions, at zero magnetic field [28][29][30][31]. The approach consists of two parts.…”

Section: The Computational Methodsmentioning

confidence: 99%

Conductance oscillations of core-shell nanowires in transversal magnetic fields

et al. 2016

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We analyze theoretically electronic transport through a core-shell nanowire in the presence of a transversal magnetic field. We calculate the conductance for a variable coupling between the nanowire and the attached leads and show how the snaking states, which are low-energy states localized along the lines of vanishing radial component of the magnetic field, manifest their existence. In the strong coupling regime they induce flux periodic, Aharonov-Bohm-like, conductance oscillations, which, by decreasing the coupling to the leads, evolve into well resolved peaks. The flux periodic oscillations arise due to interference of the snaking states, which is a consequence of backscattering at either the contacts with leads or magnetic/potential barriers in the wire.

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“…Nonetheless, the resonance can be sharp. Because of the existence of various stable periodic orbits in the system with different orbital length, sharp resonances can occur at a discrete set of energy values [19], corresponding to the "einselection" states [7,15,17]. Due to the long dwelling time near a stable periodic orbit, associated with the resonance is degradation of wave coherence [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Spin Fano Resonances and Control in Two-Dimensional Mesoscopic Transport

et al. 2020

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In electronic transport through mesoscopic systems, the various resonances in quantities such as conductance and scattering cross sections are characterized by the universal Fano formula. Does a similar formula exist for spin transport? We provide an affirmative answer by deriving a Fano formula to characterize the resonances associated with two fundamental quantities underlying spin transport: spin-resolved transmission and spin polarization vector. In particular, we generalize the conventional Green's function formalism to spin transport and use the Fisher-Lee relation to obtain the spin resolved transmission matrix, which enables the spin polarization vector to be calculated, leading to a universal Fano formula for spin resonances. Particularly, the theoretically obtained resonance width depends on the nature of the classical dynamics as determined by the geometric shape of the dot. We explicitly demonstrate this fact and argue that it can be exploited to smooth out or even eliminate Fano spin resonances by manipulating the classical dynamics, which can be realized by applying or withdrawing a properly designed local gate potential. Likewise, modulating the classical dynamics in a different way can enhance the resonance. This is of particular importance in the design of electronic switches that can control spin orientation of the electrons associated with the output current through weakening or enhancement of a Fano resonance, which are a key component in spintronics.

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Fano regime of transport through open quantum dots

Cited by 17 publications

References 44 publications

Algorithm for efficient elastic transport calculations for arbitrary device geometries

Algorithm for efficient elastic transport calculations for arbitrary device geometries

Conductance oscillations of core-shell nanowires in transversal magnetic fields

Spin Fano Resonances and Control in Two-Dimensional Mesoscopic Transport

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