%0 Journal Article
%T Multiband superconductivity with unexpected deficiency of nodal quasiparticles in CeCu2Si2
%A Shunichiro Kittaka
%A Yuya Aoki
%A Yasuyuki Shimura
%A Toshiro Sakakibara
%A Silvia Seiro
%A Christoph Geibel
%A Frank Steglich
%A Hiroaki Ikeda
%A Kazushige Machida
%J Physics
%D 2013
%I arXiv
%R 10.1103/PhysRevLett.112.067002
%X Superconductivity in the heavy-fermion compound CeCu2Si2 is a prototypical example of Cooper pairs formed by strongly correlated electrons. For more than 30 years, it has been believed to arise from nodal d-wave pairing mediated by a magnetic glue. Here, we report a detailed study of the specific heat and magnetization at low temperatures for a high-quality single crystal. Unexpectedly, the specific-heat measurements exhibit exponential decay with a two-gap feature in its temperature dependence, along with a linear dependence as a function of magnetic field and the absence of oscillations in the field angle, reminiscent of multiband full-gap superconductivity. In addition, we find anomalous behavior at high fields, attributed to a strong Pauli paramagnetic effect. A low quasiparticle density of states at low energies with a multiband Fermi-surface topology would open a new door into electron pairing in CeCu2Si2.
%U http://arxiv.org/abs/1307.3499v2