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Full-Text Articles in Physics
Influence Of The Third Dimension Of Quasi-Two-Dimensional Cuprate Superconductors On Angle-Resolved Photoemission Spectra, A. Bansil, M. Lindroos, S. Sahrakorpi, R. S. Markiewicz
Influence Of The Third Dimension Of Quasi-Two-Dimensional Cuprate Superconductors On Angle-Resolved Photoemission Spectra, A. Bansil, M. Lindroos, S. Sahrakorpi, R. S. Markiewicz
Robert Markiewicz
Angle-resolved photoemission spectroscopy (ARPES) presents significant simplifications in analyzing strictly two-dimensional (2D) materials, but even the most anisotropic physical systems display some residual three-dimensionality. Here we demonstrate how this third dimension manifests itself in ARPES spectra of quasi-2D materials by considering the example of the cuprate Bi₂Sr₂CaCu₂O₈ (Bi2212). The intercell, interlayer hopping, which is responsible for kz dispersion of the bands, is found to induce an irreducible broadening to the ARPES line shapes with a characteristic dependence on the in-plane momentum k‖. Our study suggests that ARPES line shapes can provide a direct spectroscopic window for establishing the existence of …
Magnetic Mechanism Of Quasiparticle Pairing In Hole-Doped Cuprate Superconductors, R. S. Markiewicz, A. Bansil
Magnetic Mechanism Of Quasiparticle Pairing In Hole-Doped Cuprate Superconductors, R. S. Markiewicz, A. Bansil
Robert Markiewicz
We have computed α2F’s for the hole-doped cuprates within the framework of the one-band Hubbard model, where the full magnetic response of the system is treated properly. The d-wave pairing weight α2Fd is found not only to contain a low-energy peak due to excitations near (π,π) expected from neutron-scattering data but also to display substantial spectral weight at higher energies due to contributions from other parts of the Brillouin zone as well as pair-breaking ferromagnetic excitations at low energies. The resulting solutions of the Eliashberg equations yield transition temperatures and gaps comparable to the experimentally observed values, suggesting that magnetic …
Gutzwiller Magnetic Phase Diagram Of The Cuprates, R. S. Markiewicz, J. Lorenzana, G. Seibold, A. Bansil
Gutzwiller Magnetic Phase Diagram Of The Cuprates, R. S. Markiewicz, J. Lorenzana, G. Seibold, A. Bansil
Robert Markiewicz
A general constructive procedure is presented for analyzing magnetic instabilities in two-dimensional materials, in terms of (predominantly) double nesting, and applied to Hartree-Fock plus random-phase approximation (HF+RPA) and Gutzwiller approximation plus RPA calculations of the Hubbard model. Applied to the cuprates, it is found that competing magnetic interactions are present only for hole doping, between half filling and the Van Hove singularity. While HF+RPA instabilities are present at all dopings (for sufficiently large Hubbard U), in a Gutzwiller approximation they are restricted to a doping range close to the range of relevance for the physical cuprates. The same model would …
One-Band Tight-Binding Model Parametrization Of The High-Tc Cuprates Including The Effect Of Kz Dispersion, R. S. Markiewicz, S. Sahrakorpi, M. Lindroos, Hsin Lin, A. Bansil
One-Band Tight-Binding Model Parametrization Of The High-Tc Cuprates Including The Effect Of Kz Dispersion, R. S. Markiewicz, S. Sahrakorpi, M. Lindroos, Hsin Lin, A. Bansil
Robert Markiewicz
We discuss the effects of interlayer hopping and the resulting kz dispersion in the cuprates within the framework of the one-band tight-binding model Hamiltonian. Specific forms of the dispersion relations in terms of the in-plane hopping parameters t, t′, t″, and t‴ and the effective interlayer hopping tz in La₂₋ₓSrₓCuO₄ (LSCO) and Nd₂₋ₓCeₓCuO₄ (NCCO) and the added intracell hopping tbi between the CuO₂ bilayers in Bi₂Sr₂CaCu₂O₈ (Bi2212) are presented. The values of the “bare” parameters are obtained via fits with the first-principles local-density-approximation- (LDA-) based band structures in LSCO, NCCO, and Bi2212. The corresponding “dressed” parameter sets which account for …
Paramagnon-Induced Dispersion Anomalies In The Cuprates, R. S. Markiewicz, S. Sahrakorpi, A. Bansil
Paramagnon-Induced Dispersion Anomalies In The Cuprates, R. S. Markiewicz, S. Sahrakorpi, A. Bansil
Robert Markiewicz
We report the self-energy associated with random-phase approximation magnetic susceptibility in the hole-doped Bi₂Sr₂CuO₆ (Bi2201) and the electron-doped Nd₂₋ₓCeₓCuO₄ (NCCO) in the overdoped regime within the framework of a one-band Hubbard model. A strong weight is found in the magnetic spectrum around (π,0) at about 360 meV in Bi2201 and 640 meV in NCCO, which yields dispersion anomalies in accord with the recently observed “waterfall” effects in the cuprates.
Optical Model-Solution To The Competition Between A Pseudogap Phase And A Charge-Transfer-Gap Phase In High-Temperature Cuprate Superconductors, Tanmoy Das, R. S. Markiewicz, A. Bansil
Optical Model-Solution To The Competition Between A Pseudogap Phase And A Charge-Transfer-Gap Phase In High-Temperature Cuprate Superconductors, Tanmoy Das, R. S. Markiewicz, A. Bansil
Robert Markiewicz
We present a theoretical framework for a quantitative understanding of the full doping dependence of the optical spectra of the cuprates. In accord with experimental observations, the computed spectra show how the high-energy charge-transfer (CT) gap features persist in the overdoped regime even after the midinfrared (MIR) peak originating from the pseudogap has collapsed in a quantum critical point. In this way, we reconcile the opposing tendencies of the MIR and CT peaks to shift in opposite directions in the optical spectra with increasing doping. The competition between the pseudogap and the CT gap also results in rapid loss of …
Dispersion Of Ordered Stripe Phases In The Cuprates, R. S. Markiewicz
Dispersion Of Ordered Stripe Phases In The Cuprates, R. S. Markiewicz
Robert Markiewicz
A phase separation model is presented for the stripe phase of the cuprates, which allows the doping dependence of the photoemission spectra to be calculated. The idealized limit of a well-ordered array of magnetic and charged stripes is analyzed, including effects of long-range Coulomb repulsion. Remarkably, down to the limit of two-cell wide stripes, the dispersion can be interpreted as essentially a superposition of the two end-phase dispersions, with superposed minigaps associated with the lattice periodicity. The largest minigap falls near the Fermi level; it can be enhanced by proximity to a (bulk) Van Hove singularity. The calculated spectra are …
Dispersion Anomalies Induced By The Low-Energy Plasmon In The Cuprates, R. S. Markiewicz, A. Bansil
Dispersion Anomalies Induced By The Low-Energy Plasmon In The Cuprates, R. S. Markiewicz, A. Bansil
Robert Markiewicz
We discuss the characteristic effects of the electron plasmon interaction resulting from the ~ 1 eV plasmon, which is a universal feature in the cuprates. Using the framework of a one-band tight binding model, we identify signatures of this low energy plasmon in the electronic structure of metallic overdoped Bi₂212 as well as half-filled insulating SCOC. The electron-plasmon interaction is found to yield renormalizations near the Fermi energy in reasonable accord with experimental observations, and to produce dispersion anomalies at higher energies.
Berryonic Matter In The Cuprates, R. S. Markiewicz
Berryonic Matter In The Cuprates, R. S. Markiewicz
Robert Markiewicz
A novel form of Jahn-Teller (JT) effect in the cuprates can be reinterpreted as a conventional JT effect on a lattice with a larger unit cell. There is a triplet of instabilities, parametrized by a pseudospin, consisting of a form of the low-temperature tetragonal phase, a charge density wave phase, and a flux phase (orbital antiferromagnet). On a single 4-Cu plaquette, the problem is of E ⊗ (b1 + b2) form. For a special choice of parameters, the model supports a dynamic JT effect, but is classically chaotic. The connection of this phase with Berryonic matter is discussed.