Experimental and Computational Determination of Optimal Boron Content in Layered Superconductor ScCBC
arXiv:2009.00787 · doi:10.1021/acs.inorgchem.0c02090
Abstract
It is generally difficult to quantify the amounts of light elements in materials because of their low X-ray-scattering power, as this means that they cannot be easily estimated via X-ray analyses. Meanwhile, the recently reported layered superconductor, ScCBC, requires a small amount of boron, which is a light element, for its structural stability. In this context, here, we quantitatively evaluate the optimal value using both the experimental and computational approaches. Using the high-pressure synthesis approach that can maintain the starting composition even after sintering, we obtain the Sc(C,B)C phase by the reaction of the previously reported ScC and B (ScBC). Our experiments demonstrate that an increase in values promotes the phase formation of the Sc(C,B)C structure; however, there appears to be an upper limit to the nominal value to form this phase. The maximum is found to correspond with the actual value of under the assumption that the sample with the same as the reported value possesses the optimal amount. Moreover, we construct the energy convex hull diagram by calculating the formation enthalpy based on first principles. Our computational results indicate that the composition of ScCBC is the most thermodynamically stable, which is reasonably consistent with the experimentally obtained value.
10 pages, 1 table, 7 figures