Regensburg 2002 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 17: Postersitzung II: Mesoskopische Systeme (1-19), Supraleiter: Theorie (20-26), Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter (27-33), Schwere Fermionen, Kondo-Systeme (34-45)
TT 17.28: Poster
Mittwoch, 13. März 2002, 14:30–18:00, A
Electronic Structure of Y and Lu Borocarbides — •Klaus Winzer1 and Stephen Dugdale2 — 1I.Physikalisches Institut, Universitaet Goettingen — 2H.H.Wills Physics Laboratory, University Bristol, UK
The Fermi surface of the nonmagnetic borocarbide superconductors YNi2B2C and LuNi2B2C were studied with the de Haas - van Alphen (dHvA) effect. Several branches of dHvA frequencies were observed in the normal state for B ∥ c on single crystals of both systems. The observed dHvA frequencies and their angular dependencies are very similar indicating the same topology of the corresponding parts of the Fermi surfaces. For YNi2B2C the self-consistent band structure was calculated in the irreducible 1/16 part of the Brillouin zone. For a detailed calculation of the Fermi surface a very dense mesh of 43911 k-points was used and 25 cross-sections parallel to the tetragonal plane were calculated between the X and the P-point. For a definite assignment of all the dHvA frequencies the angular dependencies of the extremal cross-section areas were also calculated. The largest cross-section areas around X and P are in very good agreement with extremal cross-section areas from the largest dHvA frequencies Fγ and Fβ. The angular dependence of the dHvA branches, the effective masses and the Fermi velocities were compared with the theoretical results.