Theoretical Investigation of High-T_c ternary superhydrides using evolutionary algorithm coupled with ab intio calculation

Recent theoretical reports on high-Tc hydride superconductors from the admixture of two binary hydrides have been successfully verified to be consistent with the experimental results. However, this is a very recent phenomenon, which needs a highly careful selection of two suitable binaries from the pool of existing binary superhydrides. Our successful theoretical prediction using evolutionary algorithm coupled with density functional theory of several high-Tc compressed superhydrides such as R¯3m-YCeH20 (122K at 300GPa)[1], R¯3m -LaCeH20 (116K at 250GPa)[1], P¯6m2-YCeH18 (173K at 150GPa)[1], Cmmm-LaYH12 (140K at 200GPa)[2], Cmmm-LaY3H24 (145K at 180GPa)[2], P4/mmm-YMgH8 (125K at 300GPa)[3], Fd¯3m -YMgH12 (190K at 200GPa)[3] is a step forward in this field. Herein, first, we perform convex-hull analysis to figure out the thermodynamically stable structure out of several thousand structures generated using evolutionary algorithm, secondly from the electron-phonon calculation, we confirm their dynamical stability followed by the prediction of their Tc employing Allen-Dynes-modified McMillan formula with Eliashberg function. Interestingly, we observed that ternary superhydrides could also show higher Tc than their parent binaries.