Impurity-Induced Local Magnetism and Density of States in the Superconducting State of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>YBa</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Cu</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>7</mml:mn></mml:msub></mml:math>

Ouazi, S.; Bobroff, J.; Alloul, H.; Tacon, M. Le; Blanchard, N.; Collin, G.; Julien, M.-H.; Horvatić, M.; Berthier, C.

doi:10.1103/physrevlett.96.127005

Cited by 39 publications

(60 citation statements)

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“…Experimentally, the enhancement of the local susceptibility was indeed found below T c [8], and tended to a large constant value at very low T . Recently, Ouazi et al [9] measured the evolution of the 17 O NMR line with increasing Zn concentration, and observed the formation of the staggered polarization cloud for the first time in the superconducting state. They argued that the primary line shift was due to the nearly field-independent vortex distribution, and that the broadening was a combination of the enhanced impurity effect and the simultaneous narrowing of the vortex field distribution due to the increased penetration depths λ in the dirtier systems.…”

Section: Introductionmentioning

confidence: 99%

Antiferromagnetic correlations and impurity broadening of NMR linewidths in cuprate superconductors

et al. 2007

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We study a model of a d-wave superconductor with strong potential scatterers in the presence of antiferromagnetic correlations and apply it to experimental nuclear magnetic resonance (NMR) results on Zn impurities in the superconducting state of YBa2Cu3O 7−δ (YBCO). We then focus on the contribution of impurity-induced paramagnetic moments, with Hubbard correlations in the host system accounted for in Hartree approximation. We show that local magnetism around individual impurities broadens the line, but quasiparticle interference between impurity states plays an important role in smearing out impurity satellite peaks. The model, together with estimates of vortex lattice effects, provides a semi-quantitative description of the impurity concentration dependence of the NMR line shape in the superconducting state, and gives a qualitative description of the temperature dependence of the line asymmetry. We argue that impurity-induced paramagnetism and resonant local density of states effects are both necessary to explain existing experiments.

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Section: Introductionmentioning

confidence: 99%

Antiferromagnetic correlations and impurity broadening of NMR linewidths in cuprate superconductors

et al. 2007

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“…With the two component model, at 3.0, 2.2, and 1.5 K respectively, we find a 1 /a s , the magnetic fraction, amounts to 0.28 (16), 0.42(6) and 0.78 (10) and λ Z , the muon spin relaxation rate, amounts to 0.22(13) × 10 6 , 0.52(9) × 10 6 and 1.29(5) × 10 6 s −1 respectively. According to this approach, as the temperature is progressively lowered a), an increasing fraction of the sample experiences electronic based magnetic fluctuations which have slowed down to enter the µSR frequency window and b), the average electron-based magnetic fluctuation rate decreases.…”

Section: Figmentioning

confidence: 70%

“…This suggests the length scale around a Ni over which the Cu(2) carry correlated magnetic moments is of the order of a few a/b lattice constants. The length scale around a Ni over which the Cu(2) carry staggered paramagnatic moments is similar 10 .…”

Section: Discussionmentioning

confidence: 98%

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Dynamic correlated Cu(2) magnetic moments in superconductingYBa2(Cu0.96Ni0.04
Hodges
¹
,
Bonville
²
,
Forget
³

et al. 2009
Phys. Rev. B
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We have examined the magnetic properties of polycrystalline, superconducting YBa2(Cu0.96Ni0.04)3Oy (y ∼7, Tsc ∼75 K) using two local probe techniques: 170 Yb Mössbauer down to 0.1 K and muon spin relaxation (µSR) down to 1.5 K. At 0.1 K, the 170 Yb measurements show the Cu(2) over essentially all the sample volume carry magnetically correlated moments which are static on the time-scale 10 −9 s. The moments show a distribution in size. The correlations are probably short range. As the temperature increases, the correlated moments are observed to fluctuate with measurable rates (in the GHz range) which increase as the temperature increases and which show a wide distribution. The µSR measurements also evidence that the fluctuation rates increase with increasing temperature and there is a distribution. The evidenced fluctuating, correlated Cu(2) moments coexist at an atomic level with superconductivity.

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“…Martin et al On the other hand, another competitive interpretation based on the Kondo effect exists. The Kondo resonance scenario [15,16] arose after the NMR experiments [17,18,19,20] which showed that the four nearest neighbor Cu atoms surrounding a Zn impurity possess local moments. These polarized spins will form the spin-singlet state with quasiparticles.…”

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Temperature dependence of the impurity-induced resonant state in Zn-dopedBi2Sr2CaCu2O8

et al. 2007

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We report on the temperature dependence of the impurity-induced resonant state in Zn-doped Bi2Sr2CaCu2O 8+δ by scanning tunneling spectroscopy at 30 mK≤ T ≤ 52 K. It is known that a Zn impurity induces a sharp resonant peak in tunnel spectrum at an energy close to the Fermi level. We observed that the resonant peak survives up to 52 K. The peak broadens with increasing temperature, which is explained by the thermal effect. This result provides information to understand the origin of the resonant peak.PACS numbers: 74.50.+r, 73.20.Hb, 74.72.Hs The scanning tunneling spectroscopy (STS) technique based on scanning tunneling microscope (STM) enables us to measure local electronic density of states (LDOS) in atomic scale. So far, there have been a lot of important studies to investigate the key mechanism of high T c cuprates by STS [1,2,3,4,5,6,7,8]. Pan et al. [4] reported STS imaging of the LDOS around impurity sites at surface of Zn-doped Bi 2 Sr 2 CaCu 2 O 8+δ (Bi2212). On the Zn site, they observed a tunnel spectrum with a sharp peak at the energy (−1.5 meV) slightly below the Fermi level (E F ) and cross-shaped fourfold quasiparticle spatial distributions. The origin of this near-zero-energy peak (NZEP) is usually considered as the impurity-scattering resonant state [9,10,11,12] because Zn-impurity has a strong scattering potential [13].Salkola and co-workers [9] considered quasiparticle scattering from a repulsive δ-potential impurity using the T -matrix approach and derived the resonant state within the superconducting gap. But it is not straightforward to explain why the LDOS on the impurity site is the largest since the Zn impurity site is a strong scattering center. Martin et al. On the other hand, another competitive interpretation based on the Kondo effect exists. The Kondo resonance scenario [15,16] arose after the NMR experiments [17,18,19,20] which showed that the four nearest neighbor Cu atoms surrounding a Zn impurity possess local moments. These polarized spins will form the spin-singlet state with quasiparticles. Note that it is not the standard Kondo effect since the density of states of the quasiparticles vanishes at the Fermi energy due to the d-wave superconducting gap structure. In this scenario, the strongest LDOS peak at Zn site can be naturally explained without considering the filter effect. However, the scenario assumes unrealistically weak potential scattering, which is not consistent with the transport measurement [13]. The origin of the NZEP is still a matter of debate.To test these scenarios, measuring the temperature evolution of the NZEP should be one of the key experiments. If the Kondo resonance scenario is correct, the peak weight of the NZEP will increase at T < T K . The value of T K is estimated about 15 K [15] from the measured peak energy of −1.5 meV [4]. In this paper, we report on the temperature dependence of NZEP in Zndoped Bi2212 in a temperature range from 30 mK to 52 K using the ultrahigh vacuum (UHV) compatible STM [21].The samples are Bi 2 Sr 2 Ca(Cu 1−x Zn x )...

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Impurity-Induced Local Magnetism and Density of States in the Superconducting State ofYBa2Cu3O7

Cited by 39 publications

References 19 publications

Antiferromagnetic correlations and impurity broadening of NMR linewidths in cuprate superconductors

Antiferromagnetic correlations and impurity broadening of NMR linewidths in cuprate superconductors

Dynamic correlated Cu(2) magnetic moments in superconductingYBa2(Cu0.96Ni0.04
Hodges
¹
,
Bonville
²
,
Forget
³

et al. 2009
Phys. Rev. B
2
0
3
0
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Temperature dependence of the impurity-induced resonant state in Zn-dopedBi2Sr2CaCu2O8

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Impurity-Induced Local Magnetism and Density of States in the Superconducting State ofYBa2Cu3O7

Cited by 39 publications

References 19 publications

Antiferromagnetic correlations and impurity broadening of NMR linewidths in cuprate superconductors

Antiferromagnetic correlations and impurity broadening of NMR linewidths in cuprate superconductors

Dynamic correlated Cu(2) magnetic moments in superconductingYBa2(Cu0.96Ni0.04Hodges1, Bonville2, Forget3 et al. 2009Phys. Rev. B2030View full textAdd to dashboardCite

Temperature dependence of the impurity-induced resonant state in Zn-dopedBi2Sr2CaCu2O8

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Dynamic correlated Cu(2) magnetic moments in superconductingYBa2(Cu0.96Ni0.04
Hodges
¹
,
Bonville
²
,
Forget
³

et al. 2009
Phys. Rev. B
2
0
3
0
View full text Add to dashboard Cite