Lithium Subhydrides Under Pressure and their Superatom-Like Building Blocks

TL;DR

This study predicts a new class of lithium-rich subhydrides stabilized under high pressure, featuring superatom-like Li8H clusters that resemble alkali metal suboxides, expanding understanding of hydrogen-rich compounds.

Contribution

The paper introduces the existence of lithium subhydrides with superatom-like clusters, identified through evolutionary structure searches and first principles calculations under high pressure.

Findings

Li8H clusters act as building blocks in subhydrides

Subhydrides are stabilized between 50-100 GPa

Structures resemble alkali metal suboxides

Abstract

Evolutionary structure searches are used to predict a new class of compounds in the lithium--rich region of the lithium/hydrogen phase diagram under pressure. First principles computations show that LimH, 4<m<9, are stabilized with respect to LiH and Li between 50-100 GPa. The building block of all of the lithium subhydrides is an Li8H cluster, which can be thought of as a superalkali. The geometries and electronic structures of these phases is analogous to that of the well-known alkali metal suboxides.