Direct observation of a Fermi surface and superconducting gap in LuNi2B2C

TitleDirect observation of a Fermi surface and superconducting gap in LuNi2B2C
Publication TypeJournal Article
Year of Publication2008
AuthorsStarowicz P, Liu C, Khasanov R, Kondo T, Samolyuk G, Gardenghi D, Lee Y, Ohta T, Harmon B, Canfield P, Bud'ko S, Rotenberg E, Kaminski A
Journal TitlePhysical Review B
Date PublishedApr
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberISI:000255457200124
Keywordsanisotropy, borocarbides, electronic-structure, intermetallic compounds, LUNIBC, single-crystals

We measured the Fermi surface (FS), band dispersion, and superconducting gap in LuNi2B2C using angle resolved photoemission spectroscopy. Experimental data were compared to the tight-binding version of the linear muffin-tin orbital (LMTO) method and linearized augmented plane-wave (LAPW) calculations. We found reasonable agreement between the two calculations and experimental data. The measured FS exhibits large parallel regions with a nesting vector that agrees with a previous positron annihilation study and calculations of the generalized susceptibility. The measured dispersion curves also agree reasonably well with the TB-LMTO calculations, although with some differences in the strength of the hybridization. In addition, the spectrum in the superconducting state revealed a 2 meV superconducting gap. The data also clearly show the presence of a coherent peak above the chemical potential mu, which originates from thermally excited electrons above the energy of 2 Delta. This feature was not previously observed in the Lu-based material.

Alternate JournalPhys. Rev. B