Fermi Surface-Brillouin Zone Interactions in 2/1-2/1-2/1 Bergman-Type Approximant Na27Au27Ga31
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Ames National Laboratory is a government-owned, contractor-operated national laboratory of the U.S. Department of Energy (DOE), operated by and located on the campus of Iowa State University in Ames, Iowa.
For more than 70 years, the Ames National Laboratory has successfully partnered with Iowa State University, and is unique among the 17 DOE laboratories in that it is physically located on the campus of a major research university. Many of the scientists and administrators at the Laboratory also hold faculty positions at the University and the Laboratory has access to both undergraduate and graduate student talent.
The Department of Chemistry seeks to provide students with a foundation in the fundamentals and application of chemical theories and processes of the lab. Thus prepared they me pursue careers as teachers, industry supervisors, or research chemists in a variety of domains (governmental, academic, etc).
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The Department of Chemistry was founded in 1880.
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1880-present
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- College of Liberal Arts and Sciences (parent college)
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Abstract
The X-ray diffraction studies on a newly synthesized Na26Au25Ga29 single crystal revealed the formation of a single phase 2/1-2/1-2/1 Bergman-type approximant and the presence of Au/Ga mixed occupancies in its unit cell containing 680 atoms. The structure model of the 2/1-2/1-2/1 approximant with composition Na27Au27Ga31 was constructed by eliminating the chemical disorder with a minimum sacrifice of composition displacement. The full potential linearized augmented plane wave electronic structure calculations with subsequent full potential linearized augmented plane wave-Fourier analysis were performed for the 2/1-2/1-2/1 approximant Na27Au27Ga31 with space group P a¯3. The square of the Fermi diameter (2kF)2, electrons per atom ratio e/a and the critical reciprocal lattice vector |G|2 are determined. A shallow pseudogap at the Fermi level was interpreted as originating from interference of electrons having (2kF)2 = 109.2 ± 1.0 with sets of lattice planes with |G|2's centered at 108. The effective e/a value for the compound is found to be 1.76 in good agreement with 1.73 derived from a composition average of (e/a)Na = 1.0, (e/a)Au = 1.0 and (e/a)Ga = 3.0.
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This is a conference proceeding from Proceedings of the 12th International Conference on Quasicrystals 126, (2014): 535, doi: 10.12693/APhysPolA.126.535. Posted with permission.