• 文献标题:   Two-Channel Charge-Kondo Physics in Graphene Quantum Dots
  • 文献类型:   Article
  • 作  者:   MINARELLI EL, RIGO JB, MITCHELL AK
  • 作者关键词:   kondo effect, graphene, electronic transport, quantum dot
  • 出版物名称:   NANOMATERIALS
  • ISSN:  
  • 通讯作者地址:  
  • 被引频次:   0
  • DOI:   10.3390/nano12091513
  • 出版年:   2022

▎ 摘  要

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.