We report the synthesis and characterization of RbNi2βSe2β, an analog of
the iron chalcogenide superconductor RbxβFe2βSe2β, via transport, angle
resolved photoemission spectroscopy, and density functional theory
calculations. A superconducting transition at Tcβ = 1.20 K is identified.
In normal state, RbNi2βSe2β shows paramagnetic and Fermi liquid behaviors.
A large Sommerfeld coefficient yields a heavy effective electron mass of
mββ6meβ. In the superconducting state, zero-field electronic
specific-heat data Cesβ can be described by a two-gap BCS model, indicating
that RbNi2βSe2β is a multi-gap superconductor. Our density functional
theory calculations and angle resolved photoemission spectroscopy measurements
demonstrate that RbNi2βSe2β exhibits relatively weak correlations and
multi-band characteristics, consistent with the multi-gap superconductivity.Comment: 7 pages, 4 figure