Two-Channel Charge-Kondo Physics in Graphene Quantum Dots
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 (2C...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-04-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/12/9/1513 |
| _version_ | 1797503497451601920 |
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| author | Emma L. Minarelli Jonas B. Rigo Andrew K. Mitchell |
| author_facet | Emma L. Minarelli Jonas B. Rigo Andrew K. Mitchell |
| author_sort | Emma L. Minarelli |
| collection | DOAJ |
| description | 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 <i>finite</i> 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. |
| first_indexed | 2024-03-10T03:51:30Z |
| format | Article |
| id | doaj.art-2c15de4ecf694277906ef5996d138be4 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-10T03:51:30Z |
| publishDate | 2022-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-2c15de4ecf694277906ef5996d138be42023-11-23T08:55:21ZengMDPI AGNanomaterials2079-49912022-04-01129151310.3390/nano12091513Two-Channel Charge-Kondo Physics in Graphene Quantum DotsEmma L. Minarelli0Jonas B. Rigo1Andrew K. Mitchell2School of Physics, University College Dublin, Dublin 4, IrelandSchool of Physics, University College Dublin, Dublin 4, IrelandSchool of Physics, University College Dublin, Dublin 4, IrelandNanoelectronic 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 <i>finite</i> 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.https://www.mdpi.com/2079-4991/12/9/1513Kondo effectgrapheneelectronic transportquantum dots |
| spellingShingle | Emma L. Minarelli Jonas B. Rigo Andrew K. Mitchell Two-Channel Charge-Kondo Physics in Graphene Quantum Dots Nanomaterials Kondo effect graphene electronic transport quantum dots |
| title | Two-Channel Charge-Kondo Physics in Graphene Quantum Dots |
| title_full | Two-Channel Charge-Kondo Physics in Graphene Quantum Dots |
| title_fullStr | Two-Channel Charge-Kondo Physics in Graphene Quantum Dots |
| title_full_unstemmed | Two-Channel Charge-Kondo Physics in Graphene Quantum Dots |
| title_short | Two-Channel Charge-Kondo Physics in Graphene Quantum Dots |
| title_sort | two channel charge kondo physics in graphene quantum dots |
| topic | Kondo effect graphene electronic transport quantum dots |
| url | https://www.mdpi.com/2079-4991/12/9/1513 |
| work_keys_str_mv | AT emmalminarelli twochannelchargekondophysicsingraphenequantumdots AT jonasbrigo twochannelchargekondophysicsingraphenequantumdots AT andrewkmitchell twochannelchargekondophysicsingraphenequantumdots |