Thermodynamic stability of Li–B–C compounds from first principles

Autor: Saba Kharabadze, Maxwell Meyers, Charlsey R. Tomassetti, Elena R. Margine, Igor I. Mazin, Aleksey N. Kolmogorov
Rok vydání: 2023
Předmět:
Zdroj: Physical Chemistry Chemical Physics. 25:7344-7353
ISSN: 1463-9084
1463-9076
DOI: 10.1039/d2cp05500g
Popis: Prediction of high-$T_{\rm{c}}$ superconductivity in hole-doped Li$_x$BC two decades ago has brought about an extensive effort to synthesize new materials with honeycomb B-C layers, but the thermodynamic stability of Li-B-C compounds remains largely unexplored. In this study, we use density functional theory to characterize well-established and recently reported Li-B-C phases. Our calculation of the Li chemical potential in Li$_x$BC helps estimate the ($T$,$P$) conditions required for delithiation of the LiBC parent material, while examination of B-C phases helps rationalize the observation of metastable BC$_3$ polymorphs with honeycomb and diamond-like morphologies. At the same time, we demonstrate that recently reported BC$_3$, LiBC$_3$, and Li$_2$B$_2$C phases with new crystal structures are both dynamically and thermodynamically unstable. With a combination of evolutionary optimization and rational design, we identify considerably more natural and favorable Li$_2$B$_2$C configurations that, nevertheless, remain above the thermodynamic stability threshold.
Databáze: OpenAIRE