Superconducting LaPtH$_{ 6 }$ with triatomic hydrogen units

TL;DR

This study investigates the La-Pt-H system at high pressure, predicting a new superconducting compound LaPtH6 with unique hydrogen units and a Tc around 19 K, but finds no evidence of hot superconductivity.

Contribution

It introduces a novel LaPtH6 compound with unique hydrogen units and predicts its superconducting properties using advanced computational methods.

Findings

LaPtH6 has equilateral triangular H3 units forming a kagome lattice.

Superconducting Tc of LaPtH6 ranges from 13.51 to 40.63 K under pressure.

No evidence of hot superconductivity was found in the La-Pt-H system.

Abstract

To veryfy "hot supreconductivity" recently proposed in lanthanum hydride-based compounds, we explored thermodynamically stable and superconducting phases in the lanthanum (La)-platinum (Pt)-hydrogen (H) ternary system at 20 GPa using an evolutionary construction scheme of a formation-enthalpy convex hull, universal neural network potential calculations, and density functional theory calculations. Although we found no evidence of the hot superconductivity in this ternary system, we predicted a unique compound, LaPtH$_{ 6 }$, which has equilateral triangular H$_{ 3 }$ units nearly forming a two-dimensional kagome lattice between La and Pt layers and shows the superconductivity at 18.67 K. This structure is dynamically stable from ambient pressure to at least 200 GPa and the superconducting critical temperature increases from 13.51 to 40.63 K.