Low Temperature Physics: 35, 687 (2009); https://doi.org/10.1063/1.3224727 (6 pages)
Физика Низких Температур: Том 35, Выпуск 8-9 (Август 2009), c. 872-878    ( к оглавлению , назад )

Magnetic quantum oscillations in borocarbide superconductors

B. Bergk and J. Wosnitza

Hochfeld-Magnetlabor Dresden (HLD), Forschungszentrum Dresden-Rossendorf, Dresden D-01314, Germany
E-mail: j.wosnitza@fzd.de

Received April 7, 2009


We report systematic de Haas–van Alphen (dHvA) investigations in the normal and superconducting state of RNi2B2C (R = Y and Lu). The observed rich frequency spectrum of the dHvA signals results from a rather complex electronic band structure with different open and closed Fermi-surface sheets. From our data in combination with full-potential local-orbital calculations we are able to extract the angular-resolved mass-enhancement factors, l, for different bands. We find a strong anisotropy and band dependence of l, clearly reflecting the multiband character of the superconductivity in RNi2B2C. We further were able to resolve dHvA oscillations deep into the superconducting state. The observed additional damping of the dHvA amplitudes is much less than expected from most theories. This hints at a reduced or even zero superconducting gap for the detected Fermi surface.

PACS: 74.70.Dd Ternary, quaternary, and multinary compounds;
PACS: 71.18.+y Fermi surface: calculations and measurements; effective mass, g factor;
PACS: 74.25.Jb Electronic structure.

Ключевые слова: superconducting state, borocarbide, oscillations, Fermi surface.