Prediction of Superconductivity in Clathrate Er Hydrides under High Pressure

In this paper, we perform unbiased structure searches combined with first-principles calculations to predict the stable structures and possible superconductivity of ErHn (n = 4~6) under pressures 50~300 GPa. Two novel compounds, ErH4 ErH6, are identified as thermodynamically dynamically above 50 GPa; ErH6 can stabilize in clathrate I4/mmm Im3¯m space groups, respectively. An analysis electronic density states (DOS) suggests metallic nature two phases. Then, superconducting critical temperature (Tc) is estimated using Allen–Dynes modified McMillan equation; results 130.9~181.2 K for Im3¯m-ErH6 at 100~300 GPa, 74.4~79.8 I4/mmm-ErH4 150~300 The resultant high Tc system be traced back combination Fermi level strong electron–phonon interactions.