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- ARPES (6)
- Bi₂Sr₂CaCu₂O₈+δ (6)
- Cuprates (6)
- La₂₋ₓSrₓCuO₄ (4)
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- Fermi energy (3)
- Bi₂Sr₂CaCu₂O₈ (2)
- Doping dependence (2)
- FS (2)
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- Angle-resolved photoemission spectroscopy (1)
- Angle-resovled photoemission spectroscopy (1)
- Anisotropic spin-correlation gab (1)
- Band inversion (1)
- Band theory (1)
- Ba₁₋ₓKₓBiO₃ (1)
- Bi-O bands (1)
- Bilayer splitting (1)
- Bi₂Sr₂CaCu₂O₈₊δ (1)
- Bi₂Sr₂CuO₆ (1)
- Block states (1)
- Bogoliubox quasiparticle scattering (1)
- Bosonic spectral function (1)
- Brillouin zone (1)
- CT gap (1)
- Ca₂₋ₓNaₓCuO₂Cl₂ (1)
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Articles 1 - 30 of 30
Full-Text Articles in Physics
Bulk Fermi Surface And Momentum Density In Heavily Doped La₂₋ₓsrₓcuo₄ Using High-Resolution Compton Scattering And Positron Annihilation Spectroscopies, W. Al-Sawai, B. Barbiellini, Y. Sakurai, M. Itou, P. Mijnarends, R. Markiewicz, S. Kaprzyk, S. Wakimoto, M. Fujita, S. Basak, H. Lin, Yung Jui Wang, S. Eijt, H. Schut, K. Yamada, A. Bansil
Bulk Fermi Surface And Momentum Density In Heavily Doped La₂₋ₓsrₓcuo₄ Using High-Resolution Compton Scattering And Positron Annihilation Spectroscopies, W. Al-Sawai, B. Barbiellini, Y. Sakurai, M. Itou, P. Mijnarends, R. Markiewicz, S. Kaprzyk, S. Wakimoto, M. Fujita, S. Basak, H. Lin, Yung Jui Wang, S. Eijt, H. Schut, K. Yamada, A. Bansil
Robert Markiewicz
We have observed the bulk Fermi surface (FS) in an overdoped (x=0.3) single crystal of La₂₋ₓSrₓCuO₄ by using Compton scattering. A two-dimensional (2D) momentum density reconstruction from measured Compton profiles yields a clear FS signature in the third Brillouin zone along [100]. The quantitative agreement between density functional theory (DFT) calculations and momentum density experiment suggests that Fermi-liquid physics is restored in the overdoped regime. In particular the predicted FS topology is found to be in good accord with the corresponding experimental data. We find similar quantitative agreement between the measured 2D angular correlation of positron annihilation radiation (2D-ACAR) spectra …
Reconstructing The Bulk Fermi Surface And Superconducting Gap Properties From Neutron Scattering Experiments, Tanmoy Das, R. S. Markiewicz, A. Bansil
Reconstructing The Bulk Fermi Surface And Superconducting Gap Properties From Neutron Scattering Experiments, Tanmoy Das, R. S. Markiewicz, A. Bansil
Robert Markiewicz
We develop an analytical tool to extract bulk electronic properties of unconventional superconductors from inelastic neutron scattering spectra. We show that the upward and downward branches of the spin excitation spectra have distinct origins, with the upper branch representing a gapped spin-wave dispersion and the lower branch associated with Bogoliubov quasiparticle scattering on the Fermi surface. Combined, they produce an "hourglass" dispersion with 45 degrees rotation of the spectrum, as found experimentally. The downward dispersion can be inverted to reveal the Fermi momentum dispersion of the single-particle spectrum as well as the corresponding superconducting (SC) gap function, analogously to the …
Emergence Of Multiple Fermi Surface Maps In Angle-Resolved Photoemission From Bi₂Sr₂Cacu₂O₈+Δ, M. C. Asensio, J. Avila, L. Roca, A. Tejeda, G. D. Gu, M. Lindroos, R. S. Markiewicz, A. Bansil
Emergence Of Multiple Fermi Surface Maps In Angle-Resolved Photoemission From Bi₂Sr₂Cacu₂O₈+Δ, M. C. Asensio, J. Avila, L. Roca, A. Tejeda, G. D. Gu, M. Lindroos, R. S. Markiewicz, A. Bansil
Robert Markiewicz
We report angle-resolved photoemission spectra (ARPES) for emission from the Fermi energy (EF) over a large area of the (kx,ky) plane using 21.2 and 32 eV photon energies in two distinct polarizations from an optimally doped single crystal of Bi₂Sr₂CaCu₂O₈₊δ (Bi2212), together with extensive first-principles simulations of the ARPES intensities. The results display a wide-ranging level of accord between theory and experiment, demonstrating that the ARPES matrix elements can produce a striking variety of Fermi surface maps, especially in the presence of secondary features arising from modulations of the underlying tetragonal system. Our analysis demonstrates how the energy and polarization …
Systematic Doping Evolution Of The Underlying Fermi Surface Of La₂₋ₓsrₓcuo₄, T. Yoshida, X. J. Zhou, K. Tanaka, W. L. Yang, Z. Hussain, Z. X. Shen, A. Fujimori, S. Sahrakorpi, M. Lindroos, R. S. Markiewicz, A. Bansil, Seiki Komiya, Yoichi Ando, H. Eisaki, T. Kakeshita, S. Uchida
Systematic Doping Evolution Of The Underlying Fermi Surface Of La₂₋ₓsrₓcuo₄, T. Yoshida, X. J. Zhou, K. Tanaka, W. L. Yang, Z. Hussain, Z. X. Shen, A. Fujimori, S. Sahrakorpi, M. Lindroos, R. S. Markiewicz, A. Bansil, Seiki Komiya, Yoichi Ando, H. Eisaki, T. Kakeshita, S. Uchida
Robert Markiewicz
We have performed a systematic doping-dependent study of La₂₋ₓSrₓCuO₄ (LSCO) (0.03 <= x <= 0.3) by angle-resolved photoemWe have performed a systematic doping-dependent study of La₂₋ₓSrxCuO₄ (LSCO) (0.03⩽x⩽0.3) by angle-resolved photoemission spectroscopy. Over this entire doping range, the underlying “Fermi surface” determined from the low-energy spectral weight approximately satisfies Luttinger’s theorem, even down to the lightly doped region. This is in strong contrast to the results on Ca₂₋ₓNaₓCuO₂Cl₂ (Na-CCOC), which show a clear deviation from Luttinger’s theorem. We correlate these differences between LSCO and Na-CCOC with differences in the behavior of chemical potential shift and spectral weight transfer induced by …
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 …
X-Ray Absorption Near-Edge Spectra Of Overdoped La₂₋ₓsrₓcuo₄ High-T(C) Superconductors, Towfiq Ahmed, Tanmoy Das, J. J. Kas, B. Barbiellini, Fernando D. Vila, R. S. Markiewicz, A. Bansil, J. J. Rehr
X-Ray Absorption Near-Edge Spectra Of Overdoped La₂₋ₓsrₓcuo₄ High-T(C) Superconductors, Towfiq Ahmed, Tanmoy Das, J. J. Kas, B. Barbiellini, Fernando D. Vila, R. S. Markiewicz, A. Bansil, J. J. Rehr
Robert Markiewicz
We present results for realistic modeling of the x-ray absorption near edge structure (XANES) of the overdoped high-Tc superconductor La₂₋ₓSrₓCuO₄ in the hole doping range x = 0.20 - 0.30. Our computations are based on a real-space Green's function approach in which strong-correlation effects are taken into account in terms of a doping-dependent self-energy. The predicted O K-edge XANES is found to be in good accord with the corresponding experimental results in this overdoped regime. We find that the low energy spectra are dominated by the contribution of O atoms in the cuprate planes, with little contribution from apical O …
Renormalization Of F Levels Away From The Fermi Energy In Electron Excitation Spectroscopies: Density-Functional Results For Nd2-Xcexcuo4, T. Jarlborg, B. Barbiellini, H. Lin, R. Markiewicz, A. Bansil
Renormalization Of F Levels Away From The Fermi Energy In Electron Excitation Spectroscopies: Density-Functional Results For Nd2-Xcexcuo4, T. Jarlborg, B. Barbiellini, H. Lin, R. Markiewicz, A. Bansil
Robert Markiewicz
Relaxation energies for photoemission where an occupied electronic state is excited and for inverse photoemission where an empty state is filled are calculated within the density-functional theory with application to Nd₂₋ₓCeₓCuO₄. The associated relaxation energies are obtained by computing differences in total energies between the ground state and an excited state in which one hole or one electron is added into the system. The relaxation energies of f electrons are found to be of the order of several eV’s, indicating that f bands will appear substantially away from the Fermi energy (EF) in their spectroscopic images, even if …
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 …
Evolution Of Midgap States And Residual Three Dimensionality In La₂₋ₓsrₓcuo₄, S. Sahrakorpi, M. Lindroos, R. Markiewicz, A. Bansil
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.
Nodeless D-Wave Superconducting Pairing Due To Residual Antiferromagnetism In Underdoped Pr2-Xcexcuo4-Δ, Tanmoy Das, R. Markiewicz, A. Bansil
Nodeless D-Wave Superconducting Pairing Due To Residual Antiferromagnetism In Underdoped Pr2-Xcexcuo4-Δ, Tanmoy Das, R. Markiewicz, A. Bansil
Robert Markiewicz
We investigate the doping dependence of the penetration depth versus temperature in electron-doped Pr₂₋ₓCeₓCuO4-δ using a model which assumes the uniform coexistence of (mean-field) antiferromagnetism and superconductivity. Despite the presence of a dₓ2₋y2 pairing gap in the underlying spectrum, we find nodeless behavior of the low-T penetration depth in the underdoped case, in accord with experimental results. As doping increases, a linear-in-T behavior of the penetration depth, characteristic of d-wave pairing, emerges as the lower magnetic band crosses the Fermi level and creates a nodal Fermi surface pocket.
Raising Bi-O Bands Above The Fermi Energy Level Of Hole-Doped Bi₂Sr₂Cacu₂O₈+Δ And Other Cuprate Superconductors, Hsin Lin, S. Sahrakorpi, R. S. Markiewicz, A. Bansil
Raising Bi-O Bands Above The Fermi Energy Level Of Hole-Doped Bi₂Sr₂Cacu₂O₈+Δ And Other Cuprate Superconductors, Hsin Lin, S. Sahrakorpi, R. S. Markiewicz, A. Bansil
Robert Markiewicz
The Fermi surface (FS) of Bi₂Sr₂CaCu₂O₈₊δ (Bi2212) predicted by band theory displays Bi-related pockets around the (π,0) point, which have never been observed experimentally. We show that when the effects of hole doping either by substituting Pb for Bi or by adding excess O in Bi2212 are included, the Bi-O bands are lifted above the Fermi energy (EF) and the resulting first-principles FS is in remarkable accord with measurements. With decreasing hole doping the Bi-O bands drop below EF and the system self-dopes below a critical hole concentration. Computations on other Bi- as well as Tl- and Hg-based compounds indicate …
Fermi-Surface Study Of Ba₁₋ₓkₓbio₃, S. Sahrakorpi, B. Barbiellini, R. Markiewicz, S. Kaprzyk, M. Lindroos, A. Bansil
Fermi-Surface Study Of Ba₁₋ₓkₓbio₃, S. Sahrakorpi, B. Barbiellini, R. Markiewicz, S. Kaprzyk, M. Lindroos, A. Bansil
Robert Markiewicz
We present all-electron computations of the three-dimensional (3D) Fermi surfaces (FS’s) in Ba₁₋ₓKₓBiO₃ for a number of different compositions based on the self-consistent Korringa-Kohn-Rostoker coherent-potential-approximation approach for incorporating the effects of Ba/K substitution. By assuming a simple cubic structure throughout the composition range, the evolution of the nesting and other features of the FS of the underlying pristine phase is correlated with the onset of various structural transitions with K doping. A parametrized scheme for obtaining an accurate 3D map of the FS in Ba₁₋ₓKₓBiO₃ for an arbitrary doping level is developed. We remark on the puzzling differences between the …
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
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 …
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 …
Spectral Decomposition And Matrix Element Effects In Scanning Tunneling Spectroscopy Of Bi₂Sr₂Cacu₂O₈₊Δ, Jouko Nieminen, Ilpo Suominen, R. Markiewicz, Hsin Lin, A. Bansil
Spectral Decomposition And Matrix Element Effects In Scanning Tunneling Spectroscopy Of Bi₂Sr₂Cacu₂O₈₊Δ, Jouko Nieminen, Ilpo Suominen, R. Markiewicz, Hsin Lin, A. Bansil
Robert Markiewicz
We present a Green’s function-based framework for modeling the scanning tunneling spectrum from the normal as well as the superconducting state of complex materials where the nature of the tunneling process—i.e., the effect of the tunneling “matrix element,” is properly taken into account. The formalism is applied to the case of optimally doped Bi₂Sr₂CaCu2=₂O8+δ (Bi2212) high-Tc superconductor using a large tight-binding basis set of electron and hole orbitals. The results show clearly that the spectrum is modified strongly by the effects of the tunneling matrix element and that it is not a simple replica of the local density of …
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
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 …
Nonmonotonic Dₓ2₋Y2 Superconducting Gap In Electron-Doped Pr0.89lace0.11cuo4: Evidence Of Coexisting Antiferromagnetism And Superconductivity?, Tanmoy Das, R. S. Markiewicz, A. Bansil
Nonmonotonic Dₓ2₋Y2 Superconducting Gap In Electron-Doped Pr0.89lace0.11cuo4: Evidence Of Coexisting Antiferromagnetism And Superconductivity?, Tanmoy Das, R. S. Markiewicz, A. Bansil
Robert Markiewicz
Recent experiments on Pr0.89LaCe0.11CuO₄ observe an anisotropic spin-correlation gap and a nonmonotonic superconducting (SC) gap, which we analyze within the framework of a t-t′-t″-t‴-tiv-U model with a dₓ2−y2 pairing interaction including a third-harmonic contribution. By introducing a realistic broadening of the quasiparticle spectrum to reflect small-angle scattering, our computations explain the experimental observations, especially the presence of a maximum in the leading-edge gap in the vicinity of the hot spots. Our analysis suggests that the material behaves like a two-band superconductor with the d-wave third harmonic acting as the interband pairing gap, and that the antiferromagnetic and SC orders coexist …
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 …
Effect Of Orbital Symmetry Of The Tip On Scanning Tunneling Spectra Of Bi₂Sr₂Cacu₂O₈+Δ, Ilpo Suominen, Jouko Nieminen, R. S. Markiewicz, A. Bansil
Effect Of Orbital Symmetry Of The Tip On Scanning Tunneling Spectra Of Bi₂Sr₂Cacu₂O₈+Δ, Ilpo Suominen, Jouko Nieminen, R. S. Markiewicz, A. Bansil
Robert Markiewicz
We discuss how variations in the scanning tunneling microscope (STM) tip, whether unintentional or intentional, can lead to changes in topographic images and dI/dV spectra. We consider the possibility of utilizing functionalized tips in order to improve the sensitivity of STM experiments to local irregularities at the surface or hidden below the surface layers. The change in the tip symmetry can radically alter the contrast of the topographic image due to changes in tip-surface overlap. The dI/dV curves change their shape according to which sample bands the tip orbital tends to overlap. In addition, relative phases between competing tunneling channels …
Induced Superconductivity In Noncuprate Layers Of The Bi₂Sr₂Cacu₂O₈+Δ High-Temperature Superconductor: Modeling Of Scanning Tunneling Spectra, Ilpo Suominen, Jouko Nieminen, R. Markiewicz, A. Bansil
Induced Superconductivity In Noncuprate Layers Of The Bi₂Sr₂Cacu₂O₈+Δ High-Temperature Superconductor: Modeling Of Scanning Tunneling Spectra, Ilpo Suominen, Jouko Nieminen, R. Markiewicz, A. Bansil
Robert Markiewicz
We analyze how the coherence peaks observed in scanning tunneling spectroscopy (STS) of cuprate high-temperature superconductors are transferred from the cuprate layer to the oxide layers adjacent to the STS microscope tip. For this purpose, we have carried out a realistic multiband calculation for the superconducting state of Bi₂Sr₂CaCu₂O₈₊δ (Bi2212) assuming a short-range d-wave pairing interaction confined to the nearest-neighbor Cu dₓ2₋y2 orbitals. The resulting anomalous matrix elements of the Green’s function allow us to monitor how pairing is then induced not only within the cuprate bilayer but also within and across other layers and …
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.
Proposal To Determine The Fermi-Surface Topology Of A Doped Iron-Based Superconductor Using Bulk-Sensitive Fourier-Transform Compton Scattering, Yung Jui Wang, Hsin Lin, B. Barbiellini, P. E. Mijnarends, S. Kaprzyk, R. S. Markiewicz, A. Bansil
Proposal To Determine The Fermi-Surface Topology Of A Doped Iron-Based Superconductor Using Bulk-Sensitive Fourier-Transform Compton Scattering, Yung Jui Wang, Hsin Lin, B. Barbiellini, P. E. Mijnarends, S. Kaprzyk, R. S. Markiewicz, A. Bansil
Robert Markiewicz
We have carried out first-principles calculations of the Compton scattering spectra to demonstrate that the filling of the hole Fermi surface in LaO₁₋ₓFₓFeAs produces a distinct signature in the Fourier-transformed Compton spectrum when the momentum transfer vector lies along the [100] direction. We thus show how the critical concentration xc
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
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.
Coexisting Pseudogap, Charge-Transfer-Gap, And Mott-Gap Energy Scales In The Resonant Inelastic X-Ray Scattering Spectra Of Electron-Doped Cuprate Superconductors, Susmita Basak, Tanmoy Das, Hsin Lin, M. Z. Hasan, R. S. Markiewicz, A. Bansil
Coexisting Pseudogap, Charge-Transfer-Gap, And Mott-Gap Energy Scales In The Resonant Inelastic X-Ray Scattering Spectra Of Electron-Doped Cuprate Superconductors, Susmita Basak, Tanmoy Das, Hsin Lin, M. Z. Hasan, R. S. Markiewicz, A. Bansil
Robert Markiewicz
We present a computation of Cu K-edge resonant inelastic x-ray scattering (RIXS) spectra for electron-doped cuprates, which includes coupling to bosonic fluctuations. Comparison with experiment over a wide range of energy and momentum transfers allows us to identify the signatures of three key normal-state energy scales: the pseudogap, charge-transfer gap, and Mott gap. The calculations involve a three-band Hubbard Hamiltonian based on dₓ2₋y2 and O pₓ, py orbitals, with a self-energy correction which arises due to spin and charge fluctuations. Our theory reproduces characteristic features, e.g., gap collapse, large spectral weight broadening, and spectral weight transfer as a function of …
Fermi Surface Evolution And Collapse Of The Mott Pseudogap In Nd2-Xcexcuo4±Δ, C. Kusko, R. S. Markiewicz, M. Lindroos, A. Bansil
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.
Origin Of The High-Energy Kink In The Photoemission Spectrum Of The High-Temperature Superconductor Bi₂Sr₂Cacu₂O₈, Susmita Basak, Tanmoy Das, Hsin Lin, J. Nieminen, M. Lindroos, R. S. Markiewicz, A. Bansil
Origin Of The High-Energy Kink In The Photoemission Spectrum Of The High-Temperature Superconductor Bi₂Sr₂Cacu₂O₈, Susmita Basak, Tanmoy Das, Hsin Lin, J. Nieminen, M. Lindroos, R. S. Markiewicz, A. Bansil
Robert Markiewicz
The high-energy kink or the waterfall effect seen in the photoemission spectra of cuprates is suggestive of the coupling of quasiparticles to a high-energy bosonic mode with implications for the mechanism of superconductivity. Recent experiments, however, indicate that this effect may be an artifact produced entirely by matrix element effects, i.e., by the way the photoemitted electron couples to incident photons in the emission process. In order to address this issue directly, we have carried out realistic computations of the photointensity in Bi₂Sr₂CaCu₂O₈ where the effects of the matrix element are included together with those of the corrections to the …
Topological Electronic Structure In Half-Heusler Topological Insulators, W. Al-Sawai, Hsin Lin, R. S. Markiewicz, L. A. Wray, Y. Xia, S. Y. Xu, M. Z. Hasan, A. Bansil
Topological Electronic Structure In Half-Heusler Topological Insulators, W. Al-Sawai, Hsin Lin, R. S. Markiewicz, L. A. Wray, Y. Xia, S. Y. Xu, M. Z. Hasan, A. Bansil
Robert Markiewicz
We have investigated band structures of a series of 28 ternary half-Heusler compounds MM'X of MgAgAs type, where M=(Lu, La, Sc, Y) and M'X=(PtBi, AuPb, PdBi, PtSb, AuSn, NiBi, PdSb). Our results show that the Z₂ topological order is due to a single band inversion at the Γ point. In native states, these half-Heusler compounds are identified as being topologically nontrivial semimetals, or nontrivial metals, or trivial insulators, which can be turned into insulating thin films on suitable substrates. Our analysis reveals a straightforward relationship which connects the band inversion strength (extent of deviation from the critical point) to the …
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 …
Single-Dirac-Cone Topological Surface States In The Tlbise₂ Class Of Topological Semiconductors, Hsin Lin, R. S. Markiewicz, L. A. Wray, L. Fu, M. Z. Hasan, A. Bansil
Single-Dirac-Cone Topological Surface States In The Tlbise₂ Class Of Topological Semiconductors, Hsin Lin, R. S. Markiewicz, L. A. Wray, L. Fu, M. Z. Hasan, A. Bansil
Robert Markiewicz
We investigate several strong spin-orbit coupling ternary chalcogenides related to the (Pb,Sn)Te series of compounds. Our first-principles calculations predict the low-temperature rhombohedral ordered phase in TlBiTe₂, TlBiSe₂, and TlSbX₂ (X=Te, Se, S) to be topologically nontrivial. We identify the specific surface termination that realizes the single Dirac cone through first-principles surface state computations. This termination minimizes effects of dangling bonds, making it favorable for photoemission experiments. In addition, our analysis predicts that thin films of these materials could harbor novel 2D quantum spin Hall states, and support odd-parity topological superconductivity.
Origin Of The Electron-Hole Asymmetry In The Scanning Tunneling Spectrum Of The High-Temperature Bi₂Sr₂Cacu₂O₈+Δ Superconductor, Jouko Nieminen, Hsin Lin, R. Markiewicz, A. Bansil
Origin Of The Electron-Hole Asymmetry In The Scanning Tunneling Spectrum Of The High-Temperature Bi₂Sr₂Cacu₂O₈+Δ Superconductor, Jouko Nieminen, Hsin Lin, R. Markiewicz, A. Bansil
Robert Markiewicz
We have developed a material specific theoretical framework for modeling scanning tunneling spectroscopy (STS) of high-temperature superconducting materials in the normal as well as the superconducting state. Results for Bi₂Sr₂CaCu₂O₈₊δ (Bi2212) show clearly that the tunneling process strongly modifies the STS spectrum from the local density of states of the dₓ2₋y2 orbital of Cu. The dominant tunneling channel to the surface Bi involves the dₓ2₋y2 orbitals of the four neighboring Cu atoms. In accord with experimental observations, the computed spectrum displays a remarkable asymmetry between the processes of electron injection and extraction, which arises from contributions of Cu dz2 and …