Probing Phase Separation and Local Lattice Distortions in Cuprates by Raman Spectroscopy

Liarokapis, E.

doi:10.3390/condmat4040087

Cited by 10 publications

(4 citation statements)

References 150 publications

(144 reference statements)

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“…This approach naturally provides a reasonable theoretical background for the phase diagram region where the nanoscale phase separation emerges near the topological Lifshitz transition. The detailed analysis of experimental evidence on the electronic phase separation in cuprate superconductors is given in review article [230].…”

Section: Electronic Phase Separation In High-t C Superconducting Cuprates and Pnictidesmentioning

confidence: 99%

Electronic phase separation: Recent progress in the old problem

2021

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Section: Electronic Phase Separation In High-t C Superconducting Cuprates and Pnictidesmentioning

confidence: 99%

Electronic phase separation: Recent progress in the old problem

2021

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“…While this enhanced electron-phonon coupling caused by localized soft vibrational modes of the oxygen atoms is irrefutable (and was shown early on in Raman experiments by Müller, Liarokapis, Kaldis and co-workers [6][7][8]), it does not fully explain the interesting phenomenology of cuprate superconductivity in its entirety. These include d-wave symmetry of the paired wavefunction, a non-Fermi liquid normal phase and the effects of magnetic correlations.…”

Section: Historical Perspective: Anharmonicity and Superconductivitymentioning

confidence: 99%

Anharmonic theory of superconductivity and its applications to emerging quantum materials

Setty,

Baggioli,

Zaccone

2024

J. Phys.: Condens. Matter

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The role of anharmonicity on superconductivity has often been disregarded in the past. Recently, it has been recognized that anharmonic decoherence could play a fundamental role in determining the superconducting properties (electron-phonon coupling, critical temperature, etc) of a large class of materials, including systems close to structural soft-mode instabilities, amorphous solids and metals under extreme high-pressure conditions.Here, we review recent theoretical progress on the role of anharmonic effects, and in particular certain universal properties of anharmonic damping, on superconductivity. Our focus regards the combination of microscopic-agnostic effective theories for bosonic mediators with the well-established BCS theory and Migdal-Eliashberg theory for superconductivity. We discuss in detail the theoretical frameworks, their possible implementation within first-principles methods, and the experimental probes for anharmonic decoherence. Finally, we present several concrete applications to emerging quantum materials, including hydrides, ferroelectrics and systems with charge density wave instabilities.

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“…Refs. [2,3,4,5]). However, a correct description of a phase-inhomogeneous state presupposes the use of an adequate physical model.…”

Section: Introductionmentioning

confidence: 99%

Phase separation in high-T$_c$ cuprates

Moskvin,

Panov

2021

Preprint

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We develop a minimal non-BCS model for the CuO2 planes with the on-site Hilbert space reduced to only three effective valence centers CuO4 with different charge, conventional spin, and orbital symmetry, combined in a charge triplet, to describe the low-energy electron structure and the phase states of HTSC cuprates. Using the S = 1 pseudospin algebra we introduce an effective spin-pseudospin Hamiltonian which takes into account local and nonlocal correlations, one-and two-particle transport, and spin exchange. To illustrate the possibilities of the molecular field approximation we start with the analysis of the atomic and the "large negative-U " limits of the model in comparison with the Bethe cluster approximation, classical and quantum Monte Carlo methods. Both limiting systems exhibit the phase separation effect typical of systems with competing order parameters. The Tn phase diagrams of the complete spin-pseudospin model were reproduced by means of a site-dependent variational approach within effective field approximation typical for spin-magnetic systems. Limiting ourselves to twosublattice approximation and nn-couplings we arrived at several Néel-like phases in CuO2 planes for parent and doped systems with a single nonzero local order parameter: antiferromagnetic insulator, charge order, glueless d-wave Bose superfluid phase, and unusual metallic phase. However, the global minimum of free energy is realized for phase separated states which are bounded by the third-order phase transition line T ⋆ (n), which is believed to be responsible for the onset of the pseudogap phenomenon. With a certain choice of the Hamiltonian parameters the model phase diagrams can quite reasonably reproduce the main features of experimental phase diagrams for T-and T ′ -cuprates and novel nickelates. The superconducting phase of cuprates/nickelates is determined by the on-site composite boson transport, it is not a consequence of pairing of doped holes/electrons, but represents one of the possible phase states of parent systems.

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Probing Phase Separation and Local Lattice Distortions in Cuprates by Raman Spectroscopy

Cited by 10 publications

References 150 publications

Electronic phase separation: Recent progress in the old problem

Electronic phase separation: Recent progress in the old problem

Anharmonic theory of superconductivity and its applications to emerging quantum materials

Phase separation in high-T$_c$ cuprates

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