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Title: Competition between Kondo effect and RKKY physics in graphene magnetism

Authors:
; ;
Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1345847
Grant/Contract Number:
SC0014407
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 10; Related Information: CHORUS Timestamp: 2017-03-06 22:10:21; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Allerdt, A., Feiguin, A. E., and Das Sarma, S. Competition between Kondo effect and RKKY physics in graphene magnetism. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.95.104402.
Allerdt, A., Feiguin, A. E., & Das Sarma, S. Competition between Kondo effect and RKKY physics in graphene magnetism. United States. doi:10.1103/PhysRevB.95.104402.
Allerdt, A., Feiguin, A. E., and Das Sarma, S. Mon . "Competition between Kondo effect and RKKY physics in graphene magnetism". United States. doi:10.1103/PhysRevB.95.104402.
@article{osti_1345847,
title = {Competition between Kondo effect and RKKY physics in graphene magnetism},
author = {Allerdt, A. and Feiguin, A. E. and Das Sarma, S.},
abstractNote = {},
doi = {10.1103/PhysRevB.95.104402},
journal = {Physical Review B},
number = 10,
volume = 95,
place = {United States},
year = {Mon Mar 06 00:00:00 EST 2017},
month = {Mon Mar 06 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevB.95.104402

Citation Metrics:
Cited by: 5works
Citation information provided by
Web of Science

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  • The transition between Kondo and Coulomb blockade effects in discontinuous double magnetic tunnel junctions is explored as a function of the size of the CoPt magnetic clusters embedded between AlO{sub x} tunnel barriers. A gradual competition between cotunneling enhancement of the tunneling magnetoresistance (TMR) and the TMR suppression due to the Kondo effect has been found in these junctions, with both effects having been found to coexist even in the same sample. It is possible to tune between these two states with temperature (at a temperature far below the cluster blocking temperature). In addition, when further decreasing the size ofmore » the CoPt clusters, another gradual transition between the Kondo effect and direct tunneling between the electrodes takes place. This second transition shows that the spin-flip processes found in junctions with impurities in the barrier are in fact due to the Kondo effect. A simple theoretical model able to account for these experimental results is proposed.« less
  • Precision electrical resistivity measurements on twelve alloys in the series CeSi/sub x/ (1.60less than or equal toxless than or equal to1.90) reflect the smooth progression from a magnetically ordered dense Kondo system (xless than or equal to1.85) to compositions where the conventional single-impurity Kondo effect dominates the exchange interaction, resulting in a ground state which is not magnetically ordered. The variations of the Kondo temperature and the magnetic ordering temperature are determined as a function of Si content and found to agree well with the theoretical Kondo-lattice model.
  • We study the Kondo chain in the regime of high spin concentration where the low energy physics is dominated by the Ruderman–Kittel–Kasuya–Yosida interaction. As has been recently shown (Tsvelik and Yevtushenko 2015 Phys. Rev. Lett. 115 216402), this model has two phases with drastically different transport properties depending on the anisotropy of the exchange interaction. In particular, the helical symmetry of the fermions is spontaneously broken when the anisotropy is of the easy plane type. This leads to a parametrical suppression of the localization effects. In the present paper we substantially extend the previous theory, in particular, by analyzing amore » competition of forward- and backward- scattering, including into the theory short range electron interactions and calculating spin correlation functions. In conclusion, we discuss applicability of our theory and possible experiments which could support the theoretical findings.« less
  • With current research efforts shifting towards the 4d and 5d transition metal oxides, understanding the evolution of the electronic and magnetic structure as one moves away from 3d materials is of critical importance. Here we perform X-ray spectroscopy and electronic structure calculations on A-site-ordered perovskites with Cu in the A-site and the B-sites descending along the ninth group of the periodic table to elucidate the emerging properties as d-orbitals change from partially filled 3d to 4d to 5d. The results show that when descending from Co to Ir, the charge transfers from the cuprate-like Zhang-Rice state on Cu to themore » t2g orbital of the B site. As the Cu d-orbital occupation approaches the Cu2þ limit, a mixed valence state in CaCu3Rh4O12 and heavy fermion state in CaCu3Ir4O12 are obtained. The investigated d-electron compounds are mapped onto the Doniach phase diagram of the competing RKKY and Kondo interactions developed for the f-electron systems.« less
  • The theory of magnetism in heavy rare earth metals is based on the RKKY theory. In this formalism the indirect exchange interaction between the local 4f spins is mediated by the conduction electrons. When carried to second order in the 4f-conduction electron interaction, traditional pertubation theory leads to a Heisenberg-like interaction between the local spins which depends on the electronic energy bands and 4f-conduction electron exchange matrix elements. This derivation neglects the detailed behavior of electron-electron interaction within the conduction band, which is known to be important in metallic systems. By using an equation of motion method, an expression formore » the inelastic neutron scattering cross-section has been derived which includes, in an approximate way, this electron-electron interaction. The results of this calculation indicate that spin-wave peaks can be broadened and shifted if the spin-wave band lies near the conduction electron Stoner continuum. The origin of this effect is similar to that found in itinerant electron systems where the spin-wave band actually intersects the Stoner continuum, resulting in the disappearance of the spin-wave mode.« less