Superconductivity in a misfit layered compound (SnSe)_1.16(NbSe₂)

Abstract

The large size single crystals of (SnSe)_1.16(NbSe₂) misfit layered compound were grown and superconductivity with T _c of 3.4 K was first discovered in this system. Powder x-ray diffraction and high resolution transmission electron microscopy clearly display the misfit feature between SnSe and NbSe₂ subsystems. The Sommerfeld coefficient γ inferred from specific-heat measurements is 16.73 mJ mol^-1 K^-2, slightly larger than the usual misfit compounds. The normalized specific heat jump [Formula: see text] is about 0.98, and the electron-phonon coupling constant [Formula: see text] is estimated to be 0.80. The estimated value of the in-plane upper critical magnetic field, [Formula: see text](0), is about 7.82 T, exceeding the Pauli paramagnetic limit slightly. Both the specific-heat and H _c2 data suggest that (SnSe)_1.16(NbSe₂) is a multi-band superconductor.