Refinement of the incommensurate structure of high quality Bi-2212 single crystals from a neutron diffraction study

Miles, Perry A.; Kennedy, S.J.; McIntyre, Garry J.; Gu, G. D.; Russell, G.J.; Koshizuka, N.

doi:10.1016/s0921-4534(97)01682-1

Cited by 47 publications

(61 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here we resolve the conflict by mapping the distribution of O i (Bi) locations into the two distinct halves of the orthorhombic unit cell. Each lattice O shifts 0.55 Å (15% of the tetragonal cell) away from the high symmetry point, 28 and we now find that O i (Bi) are located on the opposite side of the unit cell from the lattice oxygen, consistent with the second most energetically favorable position "He2", shown in Fig. 1c.…”

supporting

confidence: 75%

“…However, none of these conflicting efforts took into account the orthorhombic structural distortion, which displaces lattice oxygens laterally by 0.55 Å in the BiO layer. 28 We acquire STM topographs and simultaneous dI/dV images of the BiO layer at +1 V, -1 V, and -1.5 V sample bias, and locate the exact positions of three types of oxygen defects with respect to the Bi lattice seen in the topographs (detailed description given in Supporting Information). Figure 2a shows a scatter plot of O i (Bi) locations within the full orthorhombic unit cell of the BiO layer.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Nanoscale Interplay of Strain and Doping in a High-Temperature Superconductor

et al. 2014

View full text Add to dashboard Cite

The highest temperature superconductors are electronically inhomogeneous at the nanoscale, suggesting the existence of a local variable which could be harnessed to enhance the superconducting pairing. Here we report the relationship between local doping and local strain in the cuprate superconductor Bi 2 Sr 2 CaCu 2 O 8+x . We use scanning tunneling microscopy to discover that the crucial oxygen dopants are periodically distributed, in correlation with local strain. Our picoscale investigation of the intra-unit-cell positions of all oxygen dopants provides essential structural input for a complete microscopic theory.Cuprate superconductors display startling nanoscale inhomogeneity in essential properties such as the spectral gap ∆, 1-3 collective mode energy Ω, 4 and even the pairing temperature T p . 5

show abstract

supporting

confidence: 75%

mentioning

confidence: 99%

Nanoscale Interplay of Strain and Doping in a High-Temperature Superconductor

et al. 2014

View full text Add to dashboard Cite

show abstract

“…2 delineates the effect of doping in orthorhombic Bi2212. 6,17,18 Here one obtains twice the number of Fig. 2(a) than in 1(a), which reflects the larger atomic displacements in Bi-O layers in the orthorhombic structure.…”

mentioning

confidence: 79%

“…We have also considered the effect of hole doping on In order to assess the effect of superlattice modulation, we have carried out a series of computations in the orthorhombic structure where the refined parameters of Miles et al 18 at various positions along the modulation were used. We found that the Bi-O pockets could not be lifted for any value of the parameters.…”

mentioning

confidence: 99%

Raising Bi-O Bands above the Fermi Energy Level of Hole-DopedBi2Sr2CaCu2O8+δand Other Cuprate Superconductors

et al. 2006

View full text Add to dashboard Cite

The Fermi surface (FS) of Bi2Sr2CaCu2O 8+δ (Bi2212) predicted by band theory displays Birelated pockets around the (π, 0) point, which have never been observed experimentally. We show that when the effects of hole doping either by substituting Pb for Bi or by adding excess O in Bi2212 are included, the Bi-O bands are lifted above the Fermi energy (EF ) and the resulting first-principles FS is in remarkable accord with measurements. With decreasing hole-doping the Bi-O bands drop below EF and the system self-dopes below a critical hole concentration. Computations on other Bias well as Tl-and Hg-based compounds indicate that lifting of the cation-derived band with hole doping is a general property of the electronic structures of the cuprates.PACS numbers: 74.72. Hs,74.25.Jb,71.18.+y, First-principles band theory computations on the cuprates have become a widely accepted tool for gaining insight into their electronic structures, spectral properties, Fermi surfaces (FS's), and as a starting point for constructing theoretical models for incorporating strong correlation effects beyond the framework of the local-density approximation (LDA) underlying such calculations 1,2,3,4 . For example, in the double layer Bicompound Bi 2 Sr 2 CaCu 2 O 8+δ (Bi2212) − perhaps the most widely investigated cuprate − the LDA generated band structure 5,6 is commonly invoked to describe the doped metallic state of the system. Band theory however clearly predicts the FS of Bi2212 to contain a FS pocket around the antinodal point M (π, 0) as a Bi-O band drops below the Fermi energy (E F ), but such FS pockets have never been observed experimentally 7 . This 'Bi-O pocket problem' is quite pervasive and occurs in other Bi-compounds. 8 Similarly, Tl-and Hg-compounds display cation-derived FS pockets, presenting a fundamental challenge for addressing on a first-principles basis issues related to the doping dependencies of the electronic structures of the cuprates.In this Letter, we show how the cation-derived band responsible for the aforemenentioned FS pockets is lifted above E F when hole doping effects are properly included in the computations. Detailed results for the case of Bi2212 are presented, where hole doping is generated either by substituting Pb for Bi or by adding excess oxygen in the Bi-O planes. With 20% Pb doping in the orthorhombic crystal structure, the Bi-O band lies ≈ 1 eV above E F and the remaining bonding and antibonding FS sheets are in remarkable accord with the angleresolved photoemission (ARPES) measurements on an overdoped Bi2212 single crystal 9 . Below a critical hole doping level, the Bi-O band falls below E F and, as a result of this self-doping effect, further reduction in the hole doping level no longer reduces the number of holes in the CuO 2 layers. We argue that the underlying mechanism at play here is that hole doping reduces the effective positive charge in the Bi-O donor layers, which then reduces the tendency of the electrons to 'flow back' and self-dope the material. We have also carried out computatio...

show abstract

“…where the + sign refers to the anti-bonding band and the -sign to the bonding band, M 0 (k f ) is the matrix element of a single layer, independent of k ⊥ f , and d denotes the separation of the CuO 2 layers in a bilayer [157,158]. The key feature of Eq.…”

Section: Arpes Matrix Element Effects On the High Energy Kinkmentioning

confidence: 99%

Intermediate coupling model of the cuprates

Das

Markiewicz

Bansil

2014

Advances in Physics

View full text Add to dashboard Cite

We review the intermediate coupling model for treating electronic correlations in the cuprates. Spectral signatures of the intermediate coupling scenario are identified and used to adduce that the cuprates fall in the intermediate rather than the weak or the strong coupling limits. A robust, 'beyond LDA' framework for obtaining wide-ranging properties of the cuprates via a GW-approximation based self-consistent self-energy correction for incorporating correlation effects is delineated. In this way, doping and temperature dependent spectra, from the undoped insulator to the overdoped metal, in the normal as well as the superconducting state, with features of both weak and strong coupling can be modeled in a material-specific manner with very few parameters. Efficacy of the model is shown by considering available spectroscopic data on electron and hole doped cuprates from angle-resolved photoemission (ARPES), scanning tunneling microscopy/spectroscopy (STM/STS), neutron scattering, inelastic light scattering, optical and other experiments. Generalizations to treat systems with multiple correlated bands such as the heavy-fermions, the ruthenates, and the actinides are discussed.

show abstract

Refinement of the incommensurate structure of high quality Bi-2212 single crystals from a neutron diffraction study

Cited by 47 publications

References 28 publications

Nanoscale Interplay of Strain and Doping in a High-Temperature Superconductor

Nanoscale Interplay of Strain and Doping in a High-Temperature Superconductor

Raising Bi-O Bands above the Fermi Energy Level of Hole-DopedBi2Sr2CaCu2O8+δand Other Cuprate Superconductors

Intermediate coupling model of the cuprates

Contact Info

Product

Resources

About