Magnetic impurities in nanotubes: From density functional theory to Kondo many-body effects

Abstract : Low-temperature electronic conductance in nanocontacts, scanning tunneling microscopy (STM), and metal break junctions involving magnetic atoms or molecules is a growing area with important unsolved theoretical problems. While the detailed relationship between contact geometry and electronic structure requires a quantitative ab initio approach such as density functional theory (DFT), the Kondo many-body effects ensuing from the coupling of the impurity spin with metal electrons are most properly addressed by formulating a generalized Anderson impurity model to be solved with, for example, the numerical renormalization group (NRG) method. Since there is at present no seamless scheme that can accurately carry out that program, we have in recent years designed a systematic method for semiquantitatively joining DFT and NRG. We apply this DFT-NRG scheme to the ideal conductance of single wall (4,4) and (8,8) nanotubes with magnetic adatoms (Co and Fe), both inside and outside the nanotube, and with a single carbon atom vacancy. A rich scenario emerges, with Kondo temperatures generally in the Kelvin range, and conductance anomalies ranging from a single channel maximum to destructive Fano interference with cancellation of two channels out of the total four. The configuration yielding the highest Kondo temperature (tens of Kelvins) and a measurable zero-bias anomaly is that of a Co or Fe impurity inside the narrowest nanotube. The single atom vacancy has a spin, but a very low Kondo temperature is predicted. The geometric, electronic, and symmetry factors influencing this variability are all accessible, which makes this approach methodologically instructive and highlights many delicate and difficult points in the first-principles modeling of the Kondo effect in nanocontacts.
Type de document :
Article dans une revue
Physical Review B : Condensed matter and materials physics, American Physical Society, 2013, 88, pp.245426. 〈10.1103/PhysRevB.88.245426〉
Liste complète des métadonnées

Littérature citée [41 références]  Voir  Masquer  Télécharger

https://hal-cea.archives-ouvertes.fr/cea-01481347
Contributeur : Dominique Girard <>
Soumis le : jeudi 2 mars 2017 - 14:38:11
Dernière modification le : vendredi 16 mars 2018 - 01:14:53
Document(s) archivé(s) le : mercredi 31 mai 2017 - 14:34:27

Fichier

PhysRevB.88.245426.pdf
Fichiers produits par l'(les) auteur(s)

Identifiants

Collections

Citation

P. P. Baruselli, R Fabrizio, Alexander Smogunov, R Requist, E Tosatti. Magnetic impurities in nanotubes: From density functional theory to Kondo many-body effects. Physical Review B : Condensed matter and materials physics, American Physical Society, 2013, 88, pp.245426. 〈10.1103/PhysRevB.88.245426〉. 〈cea-01481347〉

Partager

Métriques

Consultations de la notice

92

Téléchargements de fichiers

55