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Selected Works

Condensed Matter Physics

Ames Laboratory

Articles 1 - 3 of 3

Full-Text Articles in Physics

Optical Properties And Electronic Structure Of Single Crystals Of Lual2 And Ybal2, S. J. Lee, S. Y. Hong, I. R. Fisher, Paul C. Canfield, Bruce N. Harmon, David W. Lynch Jan 2015

Optical Properties And Electronic Structure Of Single Crystals Of Lual2 And Ybal2, S. J. Lee, S. Y. Hong, I. R. Fisher, Paul C. Canfield, Bruce N. Harmon, David W. Lynch

David W. Lynch

The optical conductivities of single crystals of LuAl2 and YbAl2 were measured by spectroscopic ellipsometry in the energy range of 1.4–5.5eV for LuAl2 and 1.4–5.2eV for YbAl2. The optical conductivity spectra of LuAl2 and YbAl2 show similar features except for a difference in magnitude. Both have peaks near 1.8–2.1eV and broad shoulders between 3.0 and 4.0eV. The shoulder is weaker in YbAl2. The band structure, density of states, and optical conductivity were calculated with the tight-binding linear muffin-tin orbital method in the atomic sphere approximation. The calculated optical conductivity ...


Fe−3s Core-Level Splitting And Local Magnetism In Fe2val, Ye Feng, M. V. Dobrotvorska, James W. Anderegg, C. G. Olson, David W. Lynch Jan 2015

Fe−3s Core-Level Splitting And Local Magnetism In Fe2val, Ye Feng, M. V. Dobrotvorska, James W. Anderegg, C. G. Olson, David W. Lynch

David W. Lynch

X-ray and soft x-ray photoelectron spectra were taken on Fe2VAl samples. The Fe−3s spectra show a shoulder on the higher binding energy side of the main peak, split by ≈4.7 eV. Based on current understanding of core-level multiplet splitting in transition-metal compounds, we believe this is direct evidence of a local moment in Fe2VAl.


Low-Energy Interband Absorption In Bcc Fe And Hcp Co, J. H. Weaver, E. Colavita, David W. Lynch, R. Rosei Jan 2015

Low-Energy Interband Absorption In Bcc Fe And Hcp Co, J. H. Weaver, E. Colavita, David W. Lynch, R. Rosei

David W. Lynch

We have examined the electronic structure of bcc Fe and single-crystal hcp Co by using optical absorptivity and thermoreflectance techniques for 0.2≤hν≤5 eV. The optical conductivities σ were calculated by Kramers-Kronig analyses. A prominent structure was observed in σ for Fe at 2.37 eV and a shoulder was observed near 0.8 eV; the latter structure was the dominant feature in the thermoreflectance spectrum. These were discussed in terms of minority-spin band interband absorption and spin-flip interband transitions. The anisotropic optical conductivities of hcp Co were discussed in terms of recent energy-band calculations.