Effect of covalency and interactions on the trigonal splitting in Na<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mi>x</mml:mi></mml:msub></mml:math>CoO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>

Aligia, A. A.

doi:10.1103/physrevb.88.075128

Cited by 10 publications

(14 citation statements)

References 52 publications

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“…The actual position of the levels is more complex because it is modified by exchange and pair hopping terms (see for example Ref. 38), but they not affect our treatment. For example, for the ground state for occupancy 2 in the antibonding E is a triplet due to Hund's rules.…”

Section: Symmetry Analysismentioning

confidence: 99%

Quantifying the leading role of the surface state in the Kondo effect of Co/Ag(111)

et al. 2018

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Using a combination of scanning tunneling spectroscopy and atomic lateral manipulation, we obtained a systematic variation of the Kondo temperature (TK) of Co atoms on Ag(111) as a function of the surface state contribution to the total density of states at the atom adsorption site (ρs). By sampling the TK of a Co atom on positions where ρs was spatially resolved beforehand, we obtain a nearly linear relationship between both magnitudes. We interpret the data on the basis of an Anderson model including orbital and spin degrees of freedom (SU(4)) in good agreement with the experimental findings. The fact that the onset of the surface band is near the Fermi level is crucial to lead to the observed linear behavior. In the light of this model, the quantitative analysis of the experimental data evidences that at least a quarter of the coupling of Co impurities with extended states takes place through the hybridization to surface states. This result is of fundamental relevance in the understanding of Kondo screening of magnetic impurities on noble metal surfaces, where bulk and surface electronic states coexist.

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Section: Symmetry Analysismentioning

confidence: 99%

Quantifying the leading role of the surface state in the Kondo effect of Co/Ag(111)

et al. 2018

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“…In this section we investigate the effects of correlations in an isolated 3d 8 configuration on the relative stability of the two possible ground states discussed above: spin triplet with total angular momentum projection L z = 0 O Ni Au with one hole with m = 1 and the other with m = −1, or two triplets with L z = ±1 (one hole with m = 0 and the other with m = ±1). We also provide an alternative estimation of the anisotropy parameter D. Since the GGA underestimates correlations that affect the orbital polarization of the d states, [28][29][30][31] this calculation is an important complement to the ab initio results presented above.…”

Section: Effects Of Correlations Inside the Nimentioning

confidence: 99%

Kondo physics in a Ni impurity embedded in O-doped Au chains

et al. 2015

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By means of ab initio calculations we study the effect of O-doping of Au chains containing a nanocontact represented by a Ni atom as a magnetic impurity. In contrast to pure Au chains, we find that with a minimun O-doping the $5d_{xz,yz}$ states of Au are pushed up, crossing the Fermi level. We also find that for certain O configurations, the Ni atom has two holes in the degenerate $3d_{xz,yz}$ orbitals, forming a spin $S=1$ due to a large Hund interaction. The coupling between the $5d_{xz,yz}$ Au bands and the $3d_{xz,yz}$ of Ni states leads to a possible realization of a two-channel $S=1$ Kondo effect. While this kind of Kondo effect is commonly found in bulk systems, it is rarely observed in low dimensions. The estimated Kondo scale of the system lies within the present achievable experimental resolution in transport measurements. Another possible scenario for certain atomic configurations is that one of the holes resides in a $3d_{z^2}$ orbital, leading to a two-stage Kondo effect, the second one with SU(4) symmetry

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“…Specifically we have taken the general form of the Coulomb interaction in this shell assuming spherical symmetry (described for example in Ref. [56]) eliminating all terms with either xy or x 2 − y 2 orbitals which are absent in the model. We have used the values of the Coulomb integrals F 2 = 0.16 eV, F 4 = 0.011 eV (as in Ref.…”

Section: Discussion On the Parametersmentioning

confidence: 99%

Two-stage three-channel Kondo physics for an FePc molecule on the Au(1 1 1) surface

Fernández¹,

Roura‐Bas²,

Camjayi³

et al. 2018

J. Phys.: Condens. Matter

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We study an impurity Anderson model to describe an iron phthalocyanine (FePc) molecule on Au(1 1 1), motivated by previous results of scanning tunneling spectroscopy (STS) and theoretical studies. The model hybridizes a spin doublet consisting in one hole at the [Formula: see text] orbital of iron and two degenerate doublets corresponding to one hole either in the 3d or in the 3d orbital (called π orbitals) with two degenerate Hund-rule triplets with one hole in the 3d orbital and another one in a π orbital. We solve the model using a slave-boson mean-field approximation (SBMFA). For reasonable parameters we can describe very well the observed STS spectrum between sample bias -60 mV to 20 mV. For these parameters the Kondo effect takes place in two stages, with different energy scales [Formula: see text] corresponding to the Kondo temperatures related with the hopping of the z and π orbitals respectively. There is a strong interference between the different channels and the Kondo temperatures, particularly the lowest one is strongly reduced compared with the value in the absence of the competing channel.

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Effect of covalency and interactions on the trigonal splitting in NaxCoO2

Cited by 10 publications

References 52 publications

Quantifying the leading role of the surface state in the Kondo effect of Co/Ag(111)

Quantifying the leading role of the surface state in the Kondo effect of Co/Ag(111)

Kondo physics in a Ni impurity embedded in O-doped Au chains

Two-stage three-channel Kondo physics for an FePc molecule on the Au(1 1 1) surface

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