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Full-Text Articles in Physical Sciences and Mathematics
Fermi Surface, Ground-State Electronic Structure, And Positron Experiments In Yba₂Cu₃O₇, A. Bansil, R. Pankaluoto, R. S. Rao, P. E. Mijnarends, W. Dlugosz, R. Prasad, L. C. Smedskjaer
Fermi Surface, Ground-State Electronic Structure, And Positron Experiments In Yba₂Cu₃O₇, A. Bansil, R. Pankaluoto, R. S. Rao, P. E. Mijnarends, W. Dlugosz, R. Prasad, L. C. Smedskjaer
Arun Bansil
We present calculations of electron-positron momentum density in YBa₂Cu₃O₇ based on band theory in the local-density approximation. Theoretical predictions are in semiquantitative accord with the corresponding two-dimensional positron-annihilation angular-correlation measurements. These results indicate that the conventional local-density-approximation band-theory picture provides a reasonable description of the ground-state electronic structure and the Fermi surface of YBa₂Cu₃O₇. Several Fermi-surface-related features are suggested in the positron spectra for the first time.
Electronic Structure Of Au70pd30 Disordered Alloy, E. Arola, C. J. Barnes, R. S. Rao, A. Bansil
Electronic Structure Of Au70pd30 Disordered Alloy, E. Arola, C. J. Barnes, R. S. Rao, A. Bansil
Arun Bansil
We present angle-resolved photoemission (normal-emission) measurements from the (100) surface of a disordered Au₇₀Pd₃₀ alloy single crystal using He i, Ne i, He ii, and Ne ii excitations. The experimental results are interpreted via fully relativistic Korringa-Kohn-Rostoker coherent-potential-approximation computations of complex-energy bands, spectral densities, and total and site-decomposed densities of states in the alloy. Our measurements and calculations indicate that the main effects of adding Pd to Au are the following: (i) the appearance of a Pd-derived d-band complex with small dispersion, distinctly above the Au d-band edge, centered about 1 eV below the Fermi energy, (ii) the Au-derived d-band …
Electronic Structure Of Copper-Rich Copper-Palladium Alloys, R. S. Rao, A. Bansil, H. Asonen, M. Pessa
Electronic Structure Of Copper-Rich Copper-Palladium Alloys, R. S. Rao, A. Bansil, H. Asonen, M. Pessa
Arun Bansil
In considering the electronic structure of (Cu-rich) CuPd alloys, we present computations of complex-energy bands and average densities of states together with the angle-resolved photoemission spectra from the (100), (111), and (110) surfaces of Cu₉₅Pd₅ and Cu₈₅Pd₁₅ single crystals. The impurity spectrum in CuPd is found to be dominated by two quite-well-separated Pd-derived impurity bands and differs sharply from the case of CuNi or AgPd systems, where only a single Ni- or Pd-related impurity structure appears in the alloy. Extensive comparisons between the theory and experiment are carried out with regard to the positions and halfwidths of the Pd-induced impurity …
Electronic Structure Of Disordered Cupd Alloys: A Two-Dimensional Positron-Annihilation Study, L. C. Smedskjaer, R. Benedek, R. W. Siegel, D. G. Legnini, M. D. Stahulak, A. Bansil
Electronic Structure Of Disordered Cupd Alloys: A Two-Dimensional Positron-Annihilation Study, L. C. Smedskjaer, R. Benedek, R. W. Siegel, D. G. Legnini, M. D. Stahulak, A. Bansil
Arun Bansil
Two-dimensional-angular-correlation experiments using positron-annihilation spectroscopy were performed on a series of disordered Cu-rich CuPd-alloy single crystals. The results are compared with theoretical calculations based on the Korringa-Kohn-Rostoker coherent-potential approximation. Our experiments confirm the theoretically predicted flattening of the alloy Fermi surface near [110] with increasing Pd concentration. The momentum densities and the two-dimensional-angular-correlation spectra around zero momentum exhibit a characteristic signature of the electronic states near the valence-band edge in the alloy.
Electronic Structure And Magnetism Of Fe$_{3-X}$V$_{X}$X (X=Si, Ga, And Al) Alloys By The Kkr-Cpa Method, A. Bansil, S. Kaprzyk, P. Mijnarends, J. Tobola
Electronic Structure And Magnetism Of Fe$_{3-X}$V$_{X}$X (X=Si, Ga, And Al) Alloys By The Kkr-Cpa Method, A. Bansil, S. Kaprzyk, P. Mijnarends, J. Tobola
Arun Bansil
We present first principles charge- and spin-selfconsistent electronic structure computations on the Heusler-type disordered alloys Fe$_{3-x}$V$_{x}$X for three different metalloids X=(Si, Ga and Al). In these calculations we use the methodology based on the Korringa-Kohn- Rostoker formalism and the coherent-potential approximation (KKR-CPA), generalized to treat disorder in multi-component complex alloys.