Novel Strontium Carbides Under Compression

TL;DR

This study predicts and characterizes new stable strontium carbide phases under high pressure, revealing diverse carbon bonding environments and potential exotic chemistry using ab initio methods.

Contribution

It systematically identifies novel Sr-C compounds at high pressures and analyzes their structures and bonding patterns, expanding understanding of high-pressure carbide chemistry.

Findings

Discovered new stable Sr-C phases up to 100 GPa.

Revealed diverse carbon environments including chains and rings.

Confirmed dynamical stability of all predicted compounds.

Abstract

Exploring the chemistry of materials at high pressures has lead to the discovery of previously unknown exotic compounds. Here, we systematically search for all thermodynamically stable Sr-C compounds under pressure (up to 100 GPa) using the ab initio evolutionary crystal structure prediction method. Our search lead to the discovery of hitherto unknown phases of SrC3, Sr2C5, Sr2C3, Sr2C, Sr3C2, and SrC. The newly discovered crystal structures feature a variety of different carbon environments ranging from isolated C anions and C-dimers to exotic polyatomic carbon anions including chains, stripes, and infinite ribbons consisting of pentagonal C5 and hexagonal C6 rings. Dynamical stability of all predicted compounds is confirmed by phonons calculations. Bader analysis unravels very diverse chemistry in these compounds and bonding patterns in some of them can be described using Zintl-Klemm rule.