Importance of Local Band Effects for Ferromagnetism in Hole-Doped<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>La</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>CuO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:math>Cuprate Superconductors

Barbiellini, B.; Jarlborg, T.

doi:10.1103/physrevlett.101.157002

Cited by 40 publications

(29 citation statements)

References 28 publications

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“…The situation resembles the weak itinerant superconducting ferromagnet Y 4 Co 3 which exhibits T 2 resistivity extending above the Curie temperature and a crossover to T 5∕3 behavior at higher temperatures (30). Thus, our findings lend support to electronic band calculations (15) and a scenario whereby substitution of Sr 2þ for La 3þ at high doping does not enhance superconductivity, but instead induces weak itinerant ferromagnetism "localized" primarily on nearby Cu atoms. The creation of local moments by Sr 2þ ions in excess of x ∼ 0.19, in the form of regions of staggered magnetization and/or weak ferromagnetism, is consistent with the saturation of the superfluid density (23) and the decline of T c in the heavily overdoped region.…”

Section: Resultssupporting

confidence: 72%

Direct search for a ferromagnetic phase in a heavily overdoped nonsuperconducting copper oxide

Sonier

Kaiser

Pacradouni

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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The doping of charge carriers into the CuO 2 planes of copper oxide Mott insulators causes a gradual destruction of antiferromagnetism and the emergence of high-temperature superconductivity. Optimal superconductivity is achieved at a doping concentration p beyond which further increases in doping cause a weakening and eventual disappearance of superconductivity. A potential explanation for this demise is that ferromagnetic fluctuations compete with superconductivity in the overdoped regime. In this case, a ferromagnetic phase at very low temperatures is predicted to exist beyond the doping concentration at which superconductivity disappears. Here we report on a direct examination of this scenario in overdoped La 2−x Sr x CuO 4 using the technique of muon spin relaxation. We detect the onset of static magnetic moments of electronic origin at low temperature in the heavily overdoped nonsuperconducting region. However, the magnetism does not exist in a commensurate long-range ordered state. Instead it appears as a dilute concentration of static magnetic moments. This finding places severe restrictions on the form of ferromagnetism that may exist in the overdoped regime. Although an extrinsic impurity cannot be absolutely ruled out as the source of the magnetism that does occur, the results presented here lend support to electronic band calculations that predict the occurrence of weak localized ferromagnetism at high doping.A ttempts within the framework of standard theories have failed to explain how high-temperature superconductivity emerges from charge carrier doping of an antiferromagnetic (AF) Mott insulator (1). The conventional Bardeen-CooperSchrieffer (BCS) theory of low-temperature superconductors (2) assumes that above the critical transition temperature (T c ) the electrons form a Landau Fermi liquid, and that superconductivity arises from pair condensation of the associated low-energy excitations (quasiparticles). What is clear in the case of copper oxides is that over the initial doping range where superconductivity first appears, ordinary Landau Fermi liquid theory does not apply. This realization has prompted theories in which the properties of the ordinary Fermi liquid are hidden (3), or alternatively only some properties of the Fermi liquid persist (4).A BCS-type theory may be applicable in the heavily overdoped region, where an ordinary Fermi liquid is observed (5-7). However, the recent proposal by Kopp et al. (8) that ferromagnetic (FM) fluctuations compete with d-wave superconductivity is a challenge to the notion that overdoped copper oxides strictly conform to such conventional wisdom. The primary motivation for their hypothesis is a strong upturn in the magnetic susceptibility immediately above T c for doping levels greater than p ∼ 0.19 (9-14). A tendency toward FM order for high charge doping (Fig. 1) is supported by electronic band calculations for super cells of La 2−x Ba x CuO 4 (15). However, these calculations favor the appearance of weak ferromagnetism about concentrated regions of ...

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Section: Resultssupporting

confidence: 72%

Direct search for a ferromagnetic phase in a heavily overdoped nonsuperconducting copper oxide

Sonier

Kaiser

Pacradouni

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…The measurements rule out the occurrence of long-range FM order, but are in accord with dilute frozen electronic moments or short-range magnetic order concentrated in dilute clusters. Consistent with the general idea of competing ferromagnetism, electronic band calculations by Barbiellini and Jarlborg [92] show that weak FM order develops about Sr-rich clusters in the heavily overdoped regime. Whether the magnetism detected by ZF-µSR is in the form of FM clusters remains to be determined.…”

Section: La 2−x Sr X Cuo 4 : Evidence For Diverse Forms Of Magnetismsupporting

confidence: 62%

High-field μSR studies of superconducting and magnetic correlations in cuprates aboveT_c

Sonier

2010

J. Phys.: Condens. Matter

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Abstract. The advent of high transverse-field muon spin rotation (TF-µSR) has led to recent µSR investigations of the magnetic-field response of cuprates above the superconducting transition temperature T c . Here the results of such experiments on hole-doped cuprates are reviewed. Although these investigations are currently ongoing, it is clear that the effects of high field on the internal magnetic field distribution of these materials is dependent upon a competition between superconductivity and magnetism. In La 2−x Sr x CuO 4 the response to the external field above T c is dominated by heterogeneous spin magnetism. However, the magnetism that dominates the observed inhomogeneous line broadening below x ∼ 0.19 is overwhelmed by the emergence of a completely different kind of magnetism in the heavily overdoped regime. The origin of the magnetism above x ∼ 0.19 is currently unknown, but its presence hints at a competition between superconductivity and magnetism that is reminiscent of the underdoped regime. In contrast, the width of the internal field distribution of underdoped YBa 2 Cu 3 O y above T c is observed to track T c and the density of superconducting carriers. This observation suggests that the magnetic response above T c is not dominated by electronic moments, but rather inhomogeneous fluctuating superconductivity.

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“…This is also confirmed by the cuts taken along the nodal direction plotted in Fig.8. The remaining discrepancy between experiment and theory could result from intrinsic or extrinsic inhomogeneity effects such as the appearance of local ferromagnetic clusters about concentrated regions of dopant atoms, 8 which have been neglected in the present simulations. Our conclusion is that the closed FS for x = 0.30 predicted by our LDA calculation is consistent both with the present Compton scattering data and with surfacesensitive ARPES results.…”

Section: Fermi Surface Resultsmentioning

confidence: 83%

Bulk Fermi surface and momentum density in heavily doped La2−xSrxCuO4
Al-Sawai
¹
,
Barbiellini
²
,
Sakurai
³

et al. 2012
Phys. Rev. B
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We have observed the bulk Fermi surface (FS) in an overdoped (x=0.3) single crystal of La2−xSrxCuO4 by using Compton scattering. A two-dimensional (2D) momentum density reconstruction from measured Compton profiles yields a clear FS signature in the third Brillouin zone along [100]. The quantitative agreement between density functional theory (DFT) calculations and momentum density experiment suggests that Fermi-liquid physics is restored in the overdoped regime. In particular the predicted FS topology is found to be in good accord with the corresponding experimental data. We find similar quantitative agreement between the measured 2D angular correlation of positron annihilation radiation (2D-ACAR) spectra and the DFT based computations. However, 2D-ACAR does not give such a clear signature of the FS in the extended momentum space in either the theory or the experiment.

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Importance of Local Band Effects for Ferromagnetism in Hole-DopedLa2CuO4Cuprate Superconductors

Cited by 40 publications

References 28 publications

Direct search for a ferromagnetic phase in a heavily overdoped nonsuperconducting copper oxide

Direct search for a ferromagnetic phase in a heavily overdoped nonsuperconducting copper oxide

High-field μSR studies of superconducting and magnetic correlations in cuprates aboveT_c

Bulk Fermi surface and momentum density in heavily doped La2−xSrxCuO4
Al-Sawai
¹
,
Barbiellini
²
,
Sakurai
³

et al. 2012
Phys. Rev. B
Self Cite
12
1
6
0
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Importance of Local Band Effects for Ferromagnetism in Hole-DopedLa2CuO4Cuprate Superconductors

Cited by 40 publications

References 28 publications

Direct search for a ferromagnetic phase in a heavily overdoped nonsuperconducting copper oxide

Direct search for a ferromagnetic phase in a heavily overdoped nonsuperconducting copper oxide

High-field μSR studies of superconducting and magnetic correlations in cuprates aboveTc

Bulk Fermi surface and momentum density in heavily doped La2−xSrxCuO4Al-Sawai1, Barbiellini2, Sakurai3 et al. 2012Phys. Rev. BSelf Cite12160View full textAdd to dashboardCite

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High-field μSR studies of superconducting and magnetic correlations in cuprates aboveT_c

Bulk Fermi surface and momentum density in heavily doped La2−xSrxCuO4
Al-Sawai
¹
,
Barbiellini
²
,
Sakurai
³

et al. 2012
Phys. Rev. B
Self Cite
12
1
6
0
View full text Add to dashboard Cite