Abstract
The superconducting properties of the layered lanthanum carbide halides La 2C 2X 2 (X=Br, I) and mixed halides are investigated. These compounds show superconductivity at 7.03(5) for X=Br and at ≈1.7 K for X=I, respectively. Selected compositions were investigated using high-resolution neutron powder diffraction measurements from room temperature to 1.5 K. Rietveld refinements of the powder patterns yield the structural parameters, in particular of the C atoms. These allow us to follow in detail the variation of the interatomic distances in the C 2 group. The low-temperature structural parameters are taken as inputs to perform Extended Hückel band structure calculations which allow us to identify a band of low dispersion along the Γ–N direction in the Brillouin zone. We discuss correlations of structural and electronic properties of the La 2C 2(X,X′) 2 phase with the superconducting transition temperatures.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call