We report on the structural and superconducting properties of the intermetallic compound BaGaGe. We find that this material undergoes a structural second-order phase transition from the distorted AlB2-type structure (1H, a = 4.3254(2) \r{A}, c = 5.1078(3) \r{A}, P6/mmm) into the CaIn2-type structure (2H, a = 4.3087(3) \r{A}, c = 10.2117(6) \r{A}, P63/mmc) at a transition temperature of TS = 253 K. We find that the structural phase-transition corresponds to a coherent buckling of the honeycomb layers, which we can interpret as a disorder-to-order transition of the atoms located within this layer. We show that the 2H-BaGaGe phase becomes superconducting at a critical temperature of Tc = 2.1 K. The bulk nature of the superconductivity in 2H-BaGaGe is confirmed by means of specific heat measurements, where we determine a value of ΔC/γTc = 1.59, which is close to the expected BCS value in the weak coupling limit.
@article{arxiv.2305.13017,
title = {Structural Phase Transition and Superconductivity in 2H-BaGaGe with Buckled Honeycomb Layers},
author = {Dorota I. Walicka and Robin Lefevre and Olivier Blacque and Sara A. Lopez-Paz and Carl W. Rischau and Antonio Cervellino and Carlos A. Triana and Fabian O. von Rohr},
journal= {arXiv preprint arXiv:2305.13017},
year = {2023}
}