Kondo route to spin inhomogeneities in the honeycomb Kitaev model
Abstract
Paramagnetic impurities in a quantum spin liquid give rise to Kondo effects with highly unusual properties. We have studied the effect of locally coupling a paramagnetic impurity with the spin1/2 honeycomb Kitaev model in its gapless spinliquid phase. The ( impurity) scaling equations are found to be insensitive to the sign of the coupling. The weak and strong coupling fixed points are stable, with the latter corresponding to a noninteracting vacancy and an interacting, spin1 defect for the antiferromagnetic and ferromagnetic cases, respectively. The ground state in the strong coupling limit in both cases has a nontrivial topology associated with a finite Z(2) flux at the impurity site. For the antiferromagnetic case, this result has been obtained straightforwardly owing to the integrability of the Kitaev model with a vacancy. The strongcoupling limit of the ferromagnetic case is, however, nonintegrable, and we address this problem through exactdiagonalization calculations with finite Kitaev fragments. Our exact diagonalization calculations indicate that the weaktostrong coupling transition and the topological phase transition occur rather close to each other and are possibly coincident. We also find an intriguing similarity between the magnetic response of the defect and the impurity susceptibility in the twochannel Kondo problem.
 Authors:
 Publication Date:
 Research Org.:
 Argonne National Lab. (ANL), Argonne, IL (United States)
 Sponsoring Org.:
 USDOE Office of Science  Office of Basic Energy Sciences  Materials Sciences and Engineering Division; Cambridge Commonwealth Trust (CCT)
 OSTI Identifier:
 1352622
 DOE Contract Number:
 AC0206CH11357
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physical Review B; Journal Volume: 94; Journal Issue: 2
 Country of Publication:
 United States
 Language:
 English
Citation Formats
Das, S. D., Dhochak, K., and Tripathi, V. Kondo route to spin inhomogeneities in the honeycomb Kitaev model. United States: N. p., 2016.
Web. doi:10.1103/PhysRevB.94.024411.
Das, S. D., Dhochak, K., & Tripathi, V. Kondo route to spin inhomogeneities in the honeycomb Kitaev model. United States. doi:10.1103/PhysRevB.94.024411.
Das, S. D., Dhochak, K., and Tripathi, V. 2016.
"Kondo route to spin inhomogeneities in the honeycomb Kitaev model". United States.
doi:10.1103/PhysRevB.94.024411.
@article{osti_1352622,
title = {Kondo route to spin inhomogeneities in the honeycomb Kitaev model},
author = {Das, S. D. and Dhochak, K. and Tripathi, V.},
abstractNote = {Paramagnetic impurities in a quantum spin liquid give rise to Kondo effects with highly unusual properties. We have studied the effect of locally coupling a paramagnetic impurity with the spin1/2 honeycomb Kitaev model in its gapless spinliquid phase. The ( impurity) scaling equations are found to be insensitive to the sign of the coupling. The weak and strong coupling fixed points are stable, with the latter corresponding to a noninteracting vacancy and an interacting, spin1 defect for the antiferromagnetic and ferromagnetic cases, respectively. The ground state in the strong coupling limit in both cases has a nontrivial topology associated with a finite Z(2) flux at the impurity site. For the antiferromagnetic case, this result has been obtained straightforwardly owing to the integrability of the Kitaev model with a vacancy. The strongcoupling limit of the ferromagnetic case is, however, nonintegrable, and we address this problem through exactdiagonalization calculations with finite Kitaev fragments. Our exact diagonalization calculations indicate that the weaktostrong coupling transition and the topological phase transition occur rather close to each other and are possibly coincident. We also find an intriguing similarity between the magnetic response of the defect and the impurity susceptibility in the twochannel Kondo problem.},
doi = {10.1103/PhysRevB.94.024411},
journal = {Physical Review B},
number = 2,
volume = 94,
place = {United States},
year = 2016,
month = 7
}

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