The stripe critical point for cuprates

Bianconi, A.; Bianconi, Ginestra; Caprara, S.; Castro, D. Di; Ōyanagi, H.; Saini, N. L.

doi:10.1088/0953-8984/12/50/326

Cited by 101 publications

(157 citation statements)

References 64 publications

(68 reference statements)

Supporting

Mentioning

147

Contrasting

Order By: Relevance

“…This result points again toward the importance of connectivity and an optimum inhomogeneity for high critical temperature (12,26). It is also in qualitative agreement with the theoretical prediction of the increase of T c in a granular superconductor on an annealed complex network with a finite cutoff (55,56). In fact, for a power-law distribution of links in a granular superconductor with an exponent α ¼ 2.6 the critical temperature is predicted to increase as a function of the cutoff with an exponent 3 − α, as observed experimentally.…”

Section: Resultssupporting

confidence: 86%

“…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: 91%

See 1 more Smart Citation

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.

113

140

View full text Add to dashboard Cite

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

show abstract

Section: Resultssupporting

confidence: 86%

Section: Discussionmentioning

confidence: 91%

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.

113

140

View full text Add to dashboard Cite

show abstract

“…The microscopic relationship between lattice structure and the stripe instability has also been studied recently by detailed experiments focusing on bond lengths, or micro-strain, in the CuO polyhedra. 41 In this work we begin with the experimental motivation provided -and quantified -by Ref. 8, that real cuprate systems are often anisotropic, and that increase of this anisotropy supports static stripe formation.…”

Section: Introductionmentioning

confidence: 97%

Lattice anisotropy as the microscopic origin of static stripes in cuprates

Normand

Kampf

2001

Phys. Rev. B

View full text Add to dashboard Cite

Structural distortions in cuprate materials offer a microscopic origin for anisotropies in electron transport in the basal plane. Using a real-space Hartree-Fock approach, we consider the ground states of the anisotropic Hubbard (tx = ty) and t-J (tx = ty, Jx = Jy) models. Symmetrical but inhomogeneous ("polaronic") charge structures in the isotropic models are altered even by rather small anisotropies to one-dimensional, stripe-like features. We find two distinct types of stripe, namely uniformly filled, antiphase domain walls and non-uniform, half-filled, in-phase ones. We characterize their properties, energies and dependence on the model parameters, including filling and anisotropy in t (and J). We discuss the connections among these results, other theoretical studies and experimental observation.

show abstract

“…We expect/show that the presence of strain results in a break-up of the stripes into short segments. Lattice strain therefore prevents the stripes from ordering over long range; a situation that is a prerequisite for most stripe theories of high temperature superconductivity [2,3,[24][25][26][27][28]. This has implications for superconductivity by producing an electronic microstructure [29] of domains of broken stripes that results in a high density of topological stripe defects [25,30,31].…”

mentioning

confidence: 99%

Structural Compliance, Misfit Strain and Stripe Nanostructures in Cuprate Superconductors: Implications and Experimental Observations

Billinge

Duxbury

2002

Int. J. Mod. Phys. B

View full text Add to dashboard Cite

Structural compliance is the ability of a crystal structure to accommodate variations in local atomic bond-lengths without incurring large strain energies. We show that the structural compliance of cuprates is relatively small, so that short, highly doped, Cu-O-Cu bonds in stripes are subject to a tensile misfit strain. We develop a model to describe the effect of misfit strain on charge ordering in the copper oxygen planes of oxide materials and illustrate some of the low energy stripe nanostructures that can result. 74.72.Dn,61.72.Lk The existence of charge stripes in high T c superconductors [1] and their relevance to the high-T c property [2,3] are hotly debated subjects at present. The tendency towards charge phase separation and stripe formation has been seen in models of strongly correlated electron systems [2][3][4][5][6]. Charge stripes have also been seen directly in strongly correlated systems such as manganites [7] and nickelates [8]. In the cuprates, convincing direct evidence for stripes comes with the observation of charge-order superlattice peaks in La 1.6−x Nd 0.4 Sr x CuO 4 , though the observation of static long-range ordered stripes correlates with poor or nonexistent superconductivity [1,9]. The interest has shifted to dynamic fluctuating short-range ordered stripes. Indirect experimental evidence exists from inelastic neutron scattering supporting their presence in La 2−x (Sr,Ba) x CuO 4 [10] and YBa 2 Cu 3 O 6+δ [11,12]. The observation of a pseudo gap in the electronic density of states above T c is even more widespread [13] and can be interpreted as originating from dynamic stripes. Of critical importance is an understanding of what prevents stripes ordering over long-range and becoming static and insulating. Here we stress the importance of lattice strain to this phenomenon.Strong coupling of doped charges to the lattice is clearly evident in the cuprates [1,11,14,15]. A direct way in which the charge couples to the lattice is through the Cu-O bond length which depends on charge filling of the Cu-O σ * covalent bond [16]. Doping holes into the CuO 2 plane reduces charge density in this bond which stabilizes and shortens the bond. This is seen experimentally as a shortening of the Cu-O bond with increasing doping [17] and has profound implications when chargestripes are present. The presence of charge stripes implies that regions of the CuO 2 plane that are heavily doped, and therefore have short bonds, coexist with undoped regions with long bonds. Experimental evidence for this coexistence has been presented in superconducting La 2−x (Sr,Ba) x CuO 4 samples [18]. We show that this results in a misfit strain that breaks up the stripes into a domain microstructure. The characteristic length-scale of the domains depends on the misfit strain and can range from nanometer to long range. The importance of elastic compliance and interface strain to texture formation has been discussed in related ferroelastic materials [19] but this is the first time it is discussed in the context of breaking...

show abstract

The stripe critical point for cuprates

Cited by 101 publications

References 64 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}

Lattice anisotropy as the microscopic origin of static stripes in cuprates

Structural Compliance, Misfit Strain and Stripe Nanostructures in Cuprate Superconductors: Implications and Experimental Observations

Contact Info

Product

Resources

About

The stripe critical point for cuprates

Cited by 101 publications

References 64 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

Lattice anisotropy as the microscopic origin of static stripes in cuprates

Structural Compliance, Misfit Strain and Stripe Nanostructures in Cuprate Superconductors: Implications and Experimental Observations

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}