title: Superconductivity in CaBi2.
abstract: Superconductivity is observed with critical temperature Tc = 2.0 K in self-flux-grown single crystals of CaBi2. This material adopts the ZrSi2 structure type with lattice parameters a = 4.696(1) Å, b = 17.081(2) Å and c = 4.611(1) Å. The crystals of CaBi2 were studied by means of magnetic susceptibility, specific heat and electrical resistivity measurements. The heat capacity jump at Tc is ΔC/γTc = 1.41, confirming bulk superconductivity; the Sommerfeld coefficient γ = 4.1 mJ mol(-1) K(-2) and the Debye temperature ΘD = 157 K. The electron-phonon coupling strength is λel-ph = 0.59, and the thermodynamic critical field Hc is low, between 111 and 124 Oe CaBi2 is a moderate coupling type-I superconductor. Results of electronic structure calculations are reported and charge densities, electronic bands, densities of states and Fermi surfaces are discussed, focusing on the effects of spin-orbit coupling and electronic property anisotropy. We find a mixed quasi-2D + 3D character in the electronic structure, which reflects the layered crystal structure of the material.
authors.affiliation: Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland. mwiniarski@mif.pg.gda.pl tomasz.klimczuk@pg.gda.pl.
authors.forename: M J
authors.initials: MJ
authors.lastname: Winiarski
authors.affiliation: Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Aleja Mickiewicza 30, 30-059 Krakow, Poland.
authors.forename: B
authors.initials: B
authors.lastname: Wiendlocha
authors.affiliation: Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Aleja Mickiewicza 30, 30-059 Krakow, Poland.
authors.forename: S
authors.initials: S
authors.lastname: Gołąb
authors.affiliation: Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Kushwaha
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PNr 1410, 50-950 Wrocław, Poland.
authors.forename: P
authors.initials: P
authors.lastname: Wiśniewski
authors.affiliation: Institute of Low Temperature and Structure Research, Polish Academy of Sciences, PNr 1410, 50-950 Wrocław, Poland.
authors.forename: D
authors.initials: D
authors.lastname: Kaczorowski
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Thompson
authors.affiliation: Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Cava
authors.affiliation: Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland. mwiniarski@mif.pg.gda.pl tomasz.klimczuk@pg.gda.pl.
authors.forename: T
authors.initials: T
authors.lastname: Klimczuk