We report the synthesis and characterization of RbNi2Se2, an analog of the iron chalcogenide superconductor RbxFe2Se2, via transport, angle resolved photoemission spectroscopy, and density functional theory calculations. A superconducting transition at Tc = 1.20 K is identified. In normal state, RbNi2Se2 shows paramagnetic and Fermi liquid behaviors. A large Sommerfeld coefficient yields a heavy effective electron mass of m∗≈6me. In the superconducting state, zero-field electronic specific-heat data Ces can be described by a two-gap BCS model, indicating that RbNi2Se2 is a multi-gap superconductor. Our density functional theory calculations and angle resolved photoemission spectroscopy measurements demonstrate that RbNi2Se2 exhibits relatively weak correlations and multi-band characteristics, consistent with the multi-gap superconductivity.
@article{arxiv.2205.00116,
title = {Single crystal growth and superconductivity in RbNi$_2$Se$_2$},
author = {Hui Liu and Xunwu Hu and Hanjie Guo and Xiao-Kun Teng and Huanpeng Bu and Zhihui Luo and Lisi Li and Zengjia Liu and Mengwu Huo and Feixiang Liang and Hualei Sun and Bing Shen and Pengcheng Dai and Robert J. Birgeneau and Dao-Xin Yao and Ming Yi and Meng Wang},
journal= {arXiv preprint arXiv:2205.00116},
year = {2022}
}