Two-Channel Charge-Kondo Physics in Graphene Quantum Dots

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Title: Two-Channel Charge-Kondo Physics in Graphene Quantum Dots
Authors: Minarelli, Emma L.Rigo, Jonas B.Mitchell, Andrew K.
Permanent link: http://hdl.handle.net/10197/12968
Date: 29-Apr-2022
Online since: 2022-07-04T15:32:20Z
Abstract: Nanoelectronic quantum dot devices exploiting the charge-Kondo paradigm have been established as versatile and accurate analogue quantum simulators of fundamental quantum impurity models. In particular, hybrid metal–semiconductor dots connected to two metallic leads realize the two-channel Kondo (2CK) model, in which Kondo screening of the dot charge pseudospin is frustrated. In this article, a two-channel charge-Kondo device made instead from graphene components is considered, realizing a pseudogapped version of the 2CK model. The model is solved using Wilson’s Numerical Renormalization Group method, uncovering a rich phase diagram as a function of dot–lead coupling strength, channel asymmetry, and potential scattering. The complex physics of this system is explored through its thermodynamic properties, scattering T-matrix, and experimentally measurable conductance. The strong coupling pseudogap Kondo phase is found to persist in the channel-asymmetric two-channel context, while in the channel-symmetric case, frustration results in a novel quantum phase transition. Remarkably, despite the vanishing density of states in the graphene leads at low energies, a finite linear conductance is found at zero temperature at the frustrated critical point, which is of a non-Fermi liquid type. Our results suggest that the graphene charge-Kondo platform offers a unique possibility to access multichannel pseudogap Kondo physics.
Funding Details: Enterprise Ireland
Irish Research Council
Type of material: Journal Article
Publisher: MDPI
Journal: Nanomaterials
Volume: 12
Issue: 9
Start page: 1
End page: 16
Copyright (published version): 2022 The Authors
Keywords: Kondo effectGrapheneElectronic transportQuantum dots
DOI: 10.3390/nano12091513
Language: en
Status of Item: Peer reviewed
ISSN: 2079-4991
This item is made available under a Creative Commons License: https://creativecommons.org/licenses/by/3.0/ie/
Appears in Collections:Physics Research Collection

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