Charge order, superconducting correlations, and positive muons

Sonier, J. E.

doi:10.1016/j.jmmm.2014.08.055

Cited by 5 publications

(5 citation statements)

References 45 publications

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“…Moreover, Λ is found to scale with the maximum value of T c for each family of compounds. These observations are explained by the occurrence of inhomogeneous SC fluctuations above T c , driven by an intrinsic rearrangement of the electronic structure 18 presumably associated with a competing order of some kind and likely related to the CO instability mentioned above.…”

Section: Introductionmentioning

confidence: 91%

“…This is presumably the source of the inhomogeneous magnetic response detected in cuprates above T c by TF-µSR. 18 The average penetration of magnetic field into the SC patches can be simulated by a generalization of the critical-state Bean model. 25 The original work of Bean assumed a uniform superconductor in which the current density in the regions through which the magnetic field penetrates is equal to its critical value J c , with the simplified assumptions that J c is a constant and independent of magnetic field.…”

Section: Independent Patch Modelmentioning

confidence: 99%

“…inhomogeneous diamagnetic response to an applied field. This is presumably the source of the inhomogeneous magnetic response detected in cuprates above T c by TF-µSR [18]. The average penetration of magnetic field into the SC patches can be simulated by a generalization of the criticalstate Bean model [25].…”

Section: Independent Patch Modelmentioning

confidence: 99%

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Charge segregation model for superconducting correlations in cuprates aboveT_c

Mello

Sonier

2014

J. Phys.: Condens. Matter

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We present a theoretical framework for understanding recent transverse field muon spin rotation (TF-µSR) experiments on cuprate superconductors in terms of localized regions of phase-coherent pairing correlations above the bulk superconducting transition temperature Tc. The local regions of phase coherence are associated with a tendency toward charge ordering, a phenomenon found recently in hole-doped cuprates. We use the Cahn-Hilliard equation as a means to phenomenologically model the inhomogeneous charge distribution of the electron system observed experimentally. For this system we perform self-consistent superconducting calculations using the Bogoliubov-deGennes method. Within this context we explore two possible scenarios: (i) the magnetic field is diamagnetically screened by the sum of varying shielding currents of isolated small-sized superconducting domains. (ii) These domains become increasingly correlated by Josephson coupling as the temperature is lowered and the main response to the applied magnetic field is from the sum of all varying tunneling currents. The results indicate that these two approaches may be used to simulate the TF-µSR data but case (ii) yields better agreement.

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Section: Introductionmentioning

confidence: 91%

Section: Independent Patch Modelmentioning

confidence: 99%

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Charge segregation model for superconducting correlations in cuprates aboveT_c

Mello

Sonier

2014

J. Phys.: Condens. Matter

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“…The contents of this section are mainly adapted from a review paper by Sonier [126]. Charge-ordering has recently been established to be a common phenomenon of hole-doped cuprates.…”

Section: Charge Ordermentioning

confidence: 99%

Universal inhomogeneous magnetic-field response in the normal state of cuprate high-Tcsuperconductors

et al. 2013

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Tremendous effort continues to be devoted to elucidating the anomalous normal state of high-temperature cuprate superconductors. Experiments on underdoped cuprates have revealed a rich phase above the superconducting transition temperature (T c) with the presence of electronic nematicity, charge-density-wave order, anomalous weak magnetic order, Cooper pairing, and superconducting fluctuations. A key finding has been the observation of nanoscale electronic inhomogeneity at the surface of Bi 2 Sr 2 CaCu 2 O 8+δ by scanning tunneling microscopy (STM). Understanding the role played by the electronic inhomogeneity in the various observed phenomena requires answers to the following questions: (i) Is there a similar degree of electronic inhomogeneity in the bulk? (ii) Does the electronic inhomogeneity observed in Bi 2 Sr 2 CaCu 2 O 8+δ have any relevance to other cuprate superconductors? To address these questions one needs a bulk technique that can distinguish between a spatially uniform and inhomogeneous system. The present thesis reports on the results of a muon spin rotation (µSR) study of the bulk of Bi 2+x Sr 2-x CaCu 2 O 8+δ , as well as pure and Ca-doped YBa 2 Cu 3 O 7-δ , which together with prior measurements reveal a universal inhomogeneous magnetic-field response of hole-doped cuprates extending to temperatures far above T c. In particular, the inhomogeneous line broadening above T c is found to scale with the maximum value for each cuprate family, indicating that the inhomogeneity in the normal state is controlled by the same energy scale as T c. Since the degree of chemical disorder is very different in the materials we have measured, the observed scaling constitutes strong evidence for an intrinsic electronic tendency toward inhomogeneity in the normal-state, from which bulk superconductivity emerges at lower temperatures.

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“…The studying of the interplay between magnetism and superconductivity in cuprates has a long history [1,2,3]. Over the last fifteen years, a wealth of experimental results has suggested the presence of the charge ordering [4,5,6,7,8,9,10,11,12,13,14] and the interplaying spin and charge orderings [15,16,17,18,19,20,21] in cuprates. Recently [22] we argued that an unique property of high-T c cuprates is related to the charge-transfer instability in the CuO 2 planes.…”

Section: Introductionmentioning

confidence: 99%

Phase diagrams of a 2D Ising spin-pseudospin model

Panov

Ulitko

Budrin

et al. 2019

Journal of Magnetism and Magnetic Materials

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We consider the competition of magnetic and charge ordering in high-Tc cuprates within the framework of the simplified static 2D spin-pseudospin model. This model is equivalent to the 2D dilute antiferromagnetic (AFM) Ising model with charged impurities. We present the mean-field results for the system under study and make a brief comparison with classical Monte Carlo (MC) calculations. Numerical simulations show that the cases of strong exchange and strong charge correlation differ qualitatively. For a strong exchange, the AFM phase is unstable with respect to the phase separation (PS) into the charge and spin subsystems, which behave like immiscible quantum liquids. An analytical expression was obtained for the PS temperature.The Hamiltonian of the static spin-pseudospin model is:where S zi is a z-projection of the on-site pseudospin S = 1 and σ zi = P 0i s zi /s is a normalized z-projection of conventional spin s = 1/2 operator, multiplied by the projection operator P 0i = 1 − S 2 iz . The ∆ = U/2 is the on-site correlation and V > 0 is the inter-site density-density interaction, J =J/s 2 > 0 is the Cu 2+ −Cu 2+ Ising spin exchange coupling, h =h/s is the external magnetic field, µ is the chemical potential, so we assume the total charge constraint, nN = S zi = const, where n is the density of doped charge. The sums run over the sites of a 2D square lattice, ij means the nearest neighbors. This spin-pseudospin model generalizes the 2D dilute AFM Ising model with charged impurities. In the limit ∆ → −∞ it reduces to the S = 1 2 Ising model with fixed magnetization. At ∆ > 0 the results can be compared with the Blume-Capel model [27,28,29] or with the Blume-Emery-Griffiths model [30].An analysis of the ground state (GS) phase diagrams was done within the mean field approach [24,25]. It was shown, that the five GS phases are realized in two limits. In a weak exchange limit, atJ < V , all the GS phases (COI, COII, COIII, FIM) correspond to the charge ordering (CO) of a checker-board type at mean charge density n. While the COI phase is the charge-ordered one without spin centers, the COII and COIII phases are diluted by the non-interacting spins distributed in one sublattice only. This ferrimagnetic spin ordering is a result of the mean-field approach, so the classical MC calculations show a paramagnetic response at low temperatures. The FIM phase is also formally ferrimagnetic. Here the AFM spin ordering is diluted by the non-interacting charges distributed in one sublattice. In a strong exchange limit, atJ > V , there are only COI phase and AFM phase with the charges distributed in both sublattices. The absence of charge transfer in the Hamiltonian (1) is the most important limitation of our present model for comparison with the actual phase diagram of cuprates. But, as shown in [31], the accounting for two-particle transport enriches the GS phase diagram of the spin-pseudospin model with superfluid and supersolid phases competing with CO phases.The paper is organized as follows. We present the mean-field result...

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Charge order, superconducting correlations, and positive muons

Cited by 5 publications

References 45 publications

Charge segregation model for superconducting correlations in cuprates aboveT_c

Charge segregation model for superconducting correlations in cuprates aboveT_c

Universal inhomogeneous magnetic-field response in the normal state of cuprate high-Tcsuperconductors

Phase diagrams of a 2D Ising spin-pseudospin model

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Charge order, superconducting correlations, and positive muons

Cited by 5 publications

References 45 publications

Charge segregation model for superconducting correlations in cuprates aboveTc

Charge segregation model for superconducting correlations in cuprates aboveTc

Universal inhomogeneous magnetic-field response in the normal state of cuprate high-Tcsuperconductors

Phase diagrams of a 2D Ising spin-pseudospin model

Contact Info

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Resources

About

Charge segregation model for superconducting correlations in cuprates aboveT_c

Charge segregation model for superconducting correlations in cuprates aboveT_c