The two-component physics in cuprates in the real space and in the momentum representation

Gor’kov, L. P.; Teǐtel'Baum, G. B.

doi:10.1088/1742-6596/108/1/012009

Cited by 22 publications

(36 citation statements)

References 31 publications

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“…Our quantitative results should be tested against theories of composite, granular superconductors proposed for cuprates (10,14,15,25,(30)(31)(32)(55)(56)(57)(58)(59)(60)(61)(62). The X-ray data indicate that these theories must take into account not only the usual superconducting proximity effects, but also the effects of the strains the two components exert on each other.…”

Section: Discussionmentioning

confidence: 90%

“…Our recent discovery (12) that better superconductivity appears with "optimal inhomogeneity" (26) of oxygen defect (Oi) ordering opens the question of the nature of the remaining disordered medium, the topic of the present paper. The separation into an ordered network and a strained embedding medium provides a basis for the two electronic components (27)(28)(29) which have been proposed as the key feature for certain theories of high temperature superconductivity (30)(31)(32).…”

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confidence: 99%

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Optimum inhomogeneity of local lattice distortions in La ₂ CuO _{4+
y}

Poccia

Ricci

Campi

et al. 2012

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

112

140

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Electronic functionalities in materials from silicon to transition metal oxides are, to a large extent, controlled by defects and their relative arrangement. Outstanding examples are the oxides of copper, where defect order is correlated with their high superconducting transition temperatures. The oxygen defect order can be highly inhomogeneous, even in optimal superconducting samples, which raises the question of the nature of the sample regions where the order does not exist but which nonetheless form the "glue" binding the ordered regions together. Here we use scanning X-ray microdiffraction (with a beam 300 nm in diameter) to show that for La 2 CuO 4þy , the glue regions contain incommensurate modulated local lattice distortions, whose spatial extent is most pronounced for the best superconducting samples. For an underdoped single crystal with mobile oxygen interstitials in the spacer La 2 O 2þy layers intercalated between the CuO 2 layers, the incommensurate modulated local lattice distortions form droplets anticorrelated with the ordered oxygen interstitials, and whose spatial extent is most pronounced for the best superconducting samples. In this simplest of high temperature superconductors, there are therefore not one, but two networks of ordered defects which can be tuned to achieve optimal superconductivity. For a given stoichiometry, the highest transition temperature is obtained when both the ordered oxygen and lattice defects form fractal patterns, as opposed to appearing in isolated spots. We speculate that the relationship between material complexity and superconducting transition temperature T c is actually underpinned by a fundamental relation between T c and the distribution of ordered defect networks supported by the materials. granular superconductors | multiband superconductivity in density wave metals | scale-free heterogeneity | imaging phase separation | X-ray illumination

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Section: Discussionmentioning

confidence: 90%

mentioning

confidence: 99%

Optimum inhomogeneity of local lattice distortions in La ₂ CuO _{4+
y}

Poccia

Ricci

Campi

et al. 2012

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

112

140

View full text Add to dashboard Cite

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“…27, 28 using: Here the numbers n Hall ( x ) and hence n 0 ( x ), n 1 are defined per unit cell, where Δ ( x ) is the activation energy. (Observe in the Supplementary information SI3 how well such a decomposition satisfies the data20).…”

Section: Resultsmentioning

confidence: 99%

Two-component energy spectrum of cuprates in the pseudogap phase and its evolution with temperature and at charge ordering

Gor’kov

Teǐtel'Baum

2015

Sci Rep

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In the search for mechanisms of high-temperature superconductivity it is critical to know the electronic spectrum in the pseudogap phase from which superconductivity evolves. The lack of angle-resolved photoemission data for every cuprate family precludes an agreement as to its structure, doping and temperature dependence and the role of charge ordering. Here we show that, in the entire Fermi-liquid-like regime that is ubiquitous in underdoped cuprates, the spectrum consists of holes on the Fermi arcs and an electronic pocket. We argue that experiments on the Hall coefficient identify the latter as a permanent feature at doped hole concentration x > 0.08–0.10, in contrast to the idea of the Fermi surface reconstruction via charge ordering. The longstanding issue of the origin of the negative Hall coefficient in YBCO and Hg1201 at low temperature is resolved: the electronic contribution prevails as mobility of the latter (evaluated by the Dingle temperature) becomes temperature independent, while the mobility of holes scattered by the short-wavelength charge density waves decreases.

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“…4 In the underdoped regime the homogeneous metallic phase competes with electronic phase separation with the formation of a complex heterogeneous phase. [5][6][7][8] The chargespin ordering and electronic phase separation are accompanied by fluctuations of the local structure that diverges from the average structure. [9][10][11][12][13][14] The defects inserted in the spacer layers to dope the copper oxide electronic structure are an additional source for the modulation of the heterogeneous electronic states near the Fermi level.…”

Section: Introductionmentioning

confidence: 99%

Fermi surface reconstruction of superoxygenated La2CuO4superconductors with ordered oxygen interstitials

Jarlborg

Bianconi

2013

Phys. Rev. B

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Novel imaging methods show that the mobile dopants in optimum doped La 2 CuO 4+y (LCO) get self-organized, instead of randomly distributed, to form an inhomogeneous network of nanoscale metallic puddles with ordered oxygen interstitials interspersed with oxygen-depleted regions. These puddles are expected to be metallic, being far from half filling because of high dopant density, and to sustain superconductivity having a size in the range 5-20 nm. However, the electronic structure of these heavily doped metallic puddles is not known. In fact the rigid-band model fails because of ordering of dopants and supercell calculations are required to obtain the Fermi surface reconstruction. We have performed advanced band calculations for a large supercell La 16 Cu 8 O 32+N where N = 1 or 2 oxygen interstitials form rows in the spacer La 16 O 16+N layers intercalated between the CuO 2 layers as determined by scanning nano x-ray diffraction. The additional occupied states made by interstitial oxygen orbitals sit well below the Fermi level (E F ) and lead to hole doping as expected. The unexpected results show that in the heavily doped puddles the altered Cu(3d)-O(2p) band hybridization at E F induces a multiband electronic structure with the formation of multiple Fermi surface spots: (a) Small gaps appear in the folded Fermi surface, (b) three minibands cross E F with reduced Fermi energies of 60, 150, and 240 meV, respectively, (c) the density of states and band mass at E F show substantial increases, and (d) spin-polarized calculations show a moderate increase of antiferromagnetic spin fluctuations. All calculated features are favorable to enhance superconductivity; however, the comparison with experimental methods probing the average electronic structure of cuprates will require the description of the electronics of a network of multigap superconducting puddles.

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The two-component physics in cuprates in the real space and in the momentum representation

Cited by 22 publications

References 31 publications

Optimum inhomogeneity of local lattice distortions in La ₂ CuO _{4+
y}

Optimum inhomogeneity of local lattice distortions in La ₂ CuO _{4+
y}

Two-component energy spectrum of cuprates in the pseudogap phase and its evolution with temperature and at charge ordering

Fermi surface reconstruction of superoxygenated La2CuO4superconductors with ordered oxygen interstitials

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The two-component physics in cuprates in the real space and in the momentum representation

Cited by 22 publications

References 31 publications

Optimum inhomogeneity of local lattice distortions in La 2 CuO 4+ y

Optimum inhomogeneity of local lattice distortions in La 2 CuO 4+ y

Two-component energy spectrum of cuprates in the pseudogap phase and its evolution with temperature and at charge ordering

Fermi surface reconstruction of superoxygenated La2CuO4superconductors with ordered oxygen interstitials

Contact Info

Product

Resources

About

Optimum inhomogeneity of local lattice distortions in La ₂ CuO _{4+
y}

Optimum inhomogeneity of local lattice distortions in La ₂ CuO _{4+
y}