NMR study of local structure in metallic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">CuO</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn><mml:mo>+</mml:mo><mml:mi mathvariant="normal">δ</mml:mi></m

Hammel, P. C.; Ap, Reyes; Cheong, S. W.; Fisk, Z.; Je, Schirber

doi:10.1103/physrevlett.71.440

Cited by 102 publications

(43 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2 indicates the unique value of the EFG in the system, the two 139 La peaks are attributed to the local tilting of the direction of the EFG at the 139 La with respect to the c axis, 22 where θ m corresponds to the angle at which the direction of the EFG is parallel to H.…”

Section: Figmentioning

confidence: 99%

139La NMR investigation in underdoped La1.93Sr0.07CuO
Baek
¹
,
Erb
²
,
Büchner
³

et al. 2012
Phys. Rev. B
13
4
23
0
View full text Add to dashboard Cite

We report139 La and 63 Cu nuclear magnetic and quadrupole resonance (NMR/NQR) studies in an underdoped La1.93Sr0.07CuO4 single crystal, focusing on the 139 La NMR in the normal state. We demonstrate that the local structural distortions in the low-temperature orthorhombic structure cause the tilting of the direction of the electric field gradient (EFG) at the nuclei from the c axis, resulting in two NMR central transition spectra at both the 139 La and 63 Cu nuclei in an external field. Taking into account the tilt angle of the EFG, the temperature dependence of the 139 La spectra allowed us to determine the 139 La Knight shift and the structural order parameter. The angle and temperature dependence of the 139 La spectrum is in perfect agreement with the macroscopic average structure and proves a displacive transition. The 139 La nuclear spin-lattice relaxation rates, T −1 1 , suggest that La1.93Sr0.07CuO4 undergoes a gradual change to a temperature-independent paramagnetic regime in the high temperature region. Both the spectra and T −1 1 of the 139 La as a function of temperature reveal a sharp anomaly around TS = 387(1) K, implying a first-order-like structural transition, and a dramatic change below ∼ 70 K arising from collective glassy spin freezing.

show abstract

Section: Figmentioning

confidence: 99%

139La NMR investigation in underdoped La1.93Sr0.07CuO
Baek
¹
,
Erb
²
,
Büchner
³

et al. 2012
Phys. Rev. B
13
4
23
0
View full text Add to dashboard Cite

show abstract

“…Thus, by studying La NMR, Hammel, et al [547] have found that in La 2 CuO 4+δ there is not a single, well-defined octahedral tilt angle in the LTO phase, but rather an extremely broad distribution, from essentially zero tilt up to some maximum value, Fig. 54.…”

Section: B Short-range Order and The Dynamical Jt Phasementioning

confidence: 99%

“…54 [547]: while the superconducting phase has a broad distribution of tilt angles, the AFI phase has a well-defined LTO tilt (the splitting of the AFI peaks is due to the magnetic field). Hence the AFI appears to be correlated with a static LTO phase, like the solitons in Fig.…”

Section: Relation To Dynamic Jt Effectmentioning

confidence: 99%

A survey of the Van Hove scenario for high-tc superconductivity with special emphasis on pseudogaps and striped phases

Markiewicz

1997

Journal of Physics and Chemistry of Solids

371

280

View full text Add to dashboard Cite

The Van Hove singularity (VHS) provides a paradigm for the study of the role of peaks in the density of states (dos) on electronic properties. More importantly, it appears to play a major role in the physics of the high-Tc superconductors, particularly since recent photoemission studies have found that the VHS is close to the Fermi level in most of the high-Tc cuprates near the composition of optimum Tc. This paper offers a comprehensive survey of the VHS model, describing both theoretical properties and experimental evidence for the picture. Special topics discussed include a survey of the Fermi surfaces of the cuprates and related compounds, and an analysis of the reliability of the slave boson approach to correlation effects. While many properties of the cuprates can be qualitatively understood by a simple rigid-band-filling model, this is inadequate for more quantitative results, since correlation effects tend to pin the Fermi level near the VHS over an extended doping range, and can lead to a nanoscale phase separation. Furthermore, the peaks in the dos lead to competition from other instabilities, both magnetic and structural (related to charge density waves). A novel form of dynamic structural instability, involving dynamic VHS-Jahn-Teller effects has been predicted. Scattered through the literature, there is considerable experimental evidence for both nanoscale phase separation of holes, and for local, possibly dynamic, structural disorder. This review attempts to gather these results into a comprehensive database, to sort the results, and to see how they fit into the Van Hove scenario. Recent experiments on underdoped cuprates are found to provide a strong confirmation that the pseudogap is driven by a splitting of the VHS degeneracy.

show abstract

“…While these domains are regularly found in STM studies when the samples are cleaved at low-temperature, they can be annealed out at high temperatures 35 . This could be caused by a 'melting' of the EPS, as is found in LCO near room temperature 36 , and can be tested by careful annealing studies. Alternatively, it may be a question of pinning the EPS.…”

Section: Domain Phasementioning

confidence: 99%

Phase separation models for cuprate stripe arrays

Markiewicz

Kusko

2002

Phys. Rev. B

View full text Add to dashboard Cite

An electronic phase separation model provides a natural explanation for a large variety of experimental results in the cuprates, including evidence for both stripes and larger domains, and a termination of the phase separation in the slightly overdoped regime, when the average hole density equals that on the charged stripes. Several models are presented for charged stripes, showing how density waves, superconductivity, and strong correlations compete with quantum size effects (QSEs) in narrow stripes. The energy bands associated with the charged stripes develop in the middle of the Mott gap, and the splitting of these bands can be understood by considering the QSE on a single ladder.

show abstract

NMR study of local structure in metallicLa2CuO4+δ

Cited by 102 publications

References 15 publications

139La NMR investigation in underdoped La1.93Sr0.07CuO
Baek
¹
,
Erb
²
,
Büchner
³

et al. 2012
Phys. Rev. B
13
4
23
0
View full text Add to dashboard Cite

139La NMR investigation in underdoped La1.93Sr0.07CuO
Baek
¹
,
Erb
²
,
Büchner
³

et al. 2012
Phys. Rev. B
13
4
23
0
View full text Add to dashboard Cite

A survey of the Van Hove scenario for high-tc superconductivity with special emphasis on pseudogaps and striped phases

Phase separation models for cuprate stripe arrays

Contact Info

Product

Resources

About

NMR study of local structure in metallicLa2CuO4+δ

Cited by 102 publications

References 15 publications

139La NMR investigation in underdoped La1.93Sr0.07CuOBaek1, Erb2, Büchner3 et al. 2012Phys. Rev. B134230View full textAdd to dashboardCite

139La NMR investigation in underdoped La1.93Sr0.07CuOBaek1, Erb2, Büchner3 et al. 2012Phys. Rev. B134230View full textAdd to dashboardCite

A survey of the Van Hove scenario for high-tc superconductivity with special emphasis on pseudogaps and striped phases

Phase separation models for cuprate stripe arrays

Contact Info

Product

Resources

About

139La NMR investigation in underdoped La1.93Sr0.07CuO
Baek
¹
,
Erb
²
,
Büchner
³

et al. 2012
Phys. Rev. B
13
4
23
0
View full text Add to dashboard Cite

139La NMR investigation in underdoped La1.93Sr0.07CuO
Baek
¹
,
Erb
²
,
Büchner
³

et al. 2012
Phys. Rev. B
13
4
23
0
View full text Add to dashboard Cite