Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

Selected Works

ARPES

Robert Markiewicz

Articles 1 - 7 of 7

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 Apr 2012

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 …


Evolution Of Midgap States And Residual Three Dimensionality In La₂₋ₓsrₓcuo₄, S. Sahrakorpi, M. Lindroos, R. Markiewicz, A. Bansil Apr 2012

Evolution Of Midgap States And Residual Three Dimensionality In La₂₋ₓsrₓcuo₄, S. Sahrakorpi, M. Lindroos, R. Markiewicz, A. Bansil

Robert Markiewicz

We carry out extensive first-principles doping-dependent computations of angle-resolved photoemission (ARPES) intensities in La₂₋ₓSrₓCuO₄ over a wide range of binding energies. Intercell hopping and the associated three dimensionality, which is usually neglected in discussing cuprate physics, is shown to play a key role in shaping the ARPES spectra. Despite the obvious importance of strong coupling effects (e.g., the presence of a lower Hubbard band coexisting with midgap states in the doped insulator), a number of salient features of the experimental ARPES spectra are captured to a surprising extent when kz dispersion is properly included in the analysis.


Bilayer Splitting And Coherence Effects In Optimal And Underdoped Bi₂Sr₂Cacu₂O₈+Δ, Y. D. Chuang, A. D. Gromko, A. V. Fedorov, Y. Aiura, K. Oka, Yoichi Ando, M. Lindroos, R. S. Markiewicz, A. Bansil, D. S. Dessau Apr 2012

Bilayer Splitting And Coherence Effects In Optimal And Underdoped Bi₂Sr₂Cacu₂O₈+Δ, Y. D. Chuang, A. D. Gromko, A. V. Fedorov, Y. Aiura, K. Oka, Yoichi Ando, M. Lindroos, R. S. Markiewicz, A. Bansil, D. S. Dessau

Robert Markiewicz

We have carried out extensive high-resolution angle-resolved photoemission (ARPES) experiments on Bi₂Sr₂CACu₂O₈₊δ samples, covering the entire doping range from the overdoped to the optimally and underdoped regimes in the normal state. Our focus is on delineating the doping dependence of the bilayer splitting which is associated with the intracell coupling of electrons between the two CuO₂ planes. We exploit the photon energy of 47 eV, where strong ARPES matrix element effects are found to provide a tremendous enhancement of the antibonding to bonding component of the bilayer split bands near (π,0), in good agreement with the predictions of corresponding first-principles …


Fermi-Surface Topology And Low-Lying Electronic Structure Of The Iron-Based Superconductor Ca₁₀(Pt₃As₈)(Fe₂As₂)₅, Madhab Neupane, Chang Liu, Su-Yang Xu, Yung-Jui Wang, Ni Ni, J. M. Allred, N. Alidoust, Hsin Lin, R. S. Markiewicz, A. Bansil, R. J. Cava, M. Z. Hasan Apr 2012

Fermi-Surface Topology And Low-Lying Electronic Structure Of The Iron-Based Superconductor Ca₁₀(Pt₃As₈)(Fe₂As₂)₅, Madhab Neupane, Chang Liu, Su-Yang Xu, Yung-Jui Wang, Ni Ni, J. M. Allred, N. Alidoust, Hsin Lin, R. S. Markiewicz, A. Bansil, R. J. Cava, M. Z. Hasan

Robert Markiewicz

We report a study of low-energy electronic structure and Fermi surface topology for the recently discovered iron-based superconductor Ca₁₀(Pt₃As₈)(Fe₂As₂)₅(the 10-3-8 phase, with Tc∼8 K), via angle-resolved photoemission spectroscopy (ARPES). Despite its triclinic crystal structure, ARPES results reveal a fourfold symmetric band structure with the absence of Dirac-cone-like Fermi dots (related to magnetism) found around the Brillouin zone corners in other iron-based superconductors. Considering that the triclinic lattice and structural supercell arise from the Pt₃As₈ intermediary layers, these results indicate that those layers couple only weakly to the FeAs layers in this new superconductor at least near the surface, which has …


Special Photon Energies For Extracting The Bosonic Spectral Function Mediating Superconductivity In Bi₂Sr₂Cacu₂O₈ Via Angle-Resolved Photoemission Spectroscopy, M. Lindroos, R. S. Markiewicz, A. Bansil Apr 2012

Special Photon Energies For Extracting The Bosonic Spectral Function Mediating Superconductivity In Bi₂Sr₂Cacu₂O₈ Via Angle-Resolved Photoemission Spectroscopy, M. Lindroos, R. S. Markiewicz, A. Bansil

Robert Markiewicz

We delineate the complex nature of the angle-resolved photoemission spectroscopy (ARPES) matrix element in Bi₂Sr₂CaCu₂O₈ and identify photon energies where the matrix element is insensitive to wave vector and/or frequency. These special photon energies provide a unique route for extracting the spectral function of the bosonic glue mediating superconductivity and for obtaining self-energies more generally via ARPES experiments.


Fermi Surface Evolution And Collapse Of The Mott Pseudogap In Nd2-Xcexcuo4±Δ, C. Kusko, R. S. Markiewicz, M. Lindroos, A. Bansil Apr 2012

Fermi Surface Evolution And Collapse Of The Mott Pseudogap In Nd2-Xcexcuo4±Δ, C. Kusko, R. S. Markiewicz, M. Lindroos, A. Bansil

Robert Markiewicz

Fermi surface (FS) maps and spectral intensities obtained recently in Nd₂₋ₓCeₓCuO₄±δ via high resolution ARPES measurements are analyzed using mean-field Hartree Fock and self-consistent renormalization computations within the framework of the one-band t-t′-t″-U Hubbard model Hamiltonian. We show that the remarkable observed crossover of the FS from small to large sheets reflects a reduction in the value of the effective Hubbard U with increasing electron doping and the collapse of the correlation induced Mott pseudogap just above optimal doping.


Competing Order Scenario Of Two-Gap Behavior In Hole-Doped Cuprates, Tanmoy Das, R. S. Markiewicz, A. Bansil Jan 2011

Competing Order Scenario Of Two-Gap Behavior In Hole-Doped Cuprates, Tanmoy Das, R. S. Markiewicz, A. Bansil

Robert Markiewicz

Angle-dependent studies of the gap function provide evidence for the coexistence of two distinct gaps in hole doped cuprates, where the gap near the nodal direction scales with the superconducting transition temperature Tc, while that in the antinodal direction scales with the pseudogap temperature. We present model calculations which show that most of the characteristic features observed in the recent angle-resolved photoemission spectroscopy (ARPES) as well as scanning tunneling microscopy (STM) two-gap studies are consistent with a scenario in which the pseudogap has a non-superconducting origin in a competing phase. Our analysis indicates that, near optimal doping, superconductivity can quench …