Composition/structure directed search for new chalcogenide compounds

Abstract

This work presents a simple scheme for finding new crystalline compounds by adapting structure types from neighbor atoms compounds. The approach is demonstrated for the selenide and sulfide families of binary compounds. It predicts ten new compounds that are not currently included in the inorganic crystal structure database (ICSD). The compounds primarily originated from a small search domain that includes near neighbors. Comparison with extended searches that include structures from binary systems of more remote atoms in the periodic table demonstrate the relative efficiency of near neighbor screening. This points at the possibility of using similar directed searches as a heuristic rule for efficiently finding new stable compounds in additional compound families.

Figures (8)

• Figure 1: Convex hulls of the binary sulfide ($A$S) systems enriched with the structure types of the corresponding selenide ($A$Se) and oxide ($A$O) compounds. The orange triangle markers represent the known compounds listed in ICSD for each system (including the pure phases of the elements). The enriching structure types from the corresponding Se and O systems are shown in cyan circles and magenta $x$-symbols, respectively. Bold lines indicate the convex hulls. The dashed lines, 0.03 eV/atom above the convex hulls, indicate the range in which compounds can be considered metastable.
• Figure 2: Convex hulls of the binary selenide ($A$Se) systems enriched with structure types of the corresponding binary sulfide ($A$S) and oxide ($A$O) compounds. The markers represent different prototypes, as in Figure \ref{['fig:1']}. The black line marking the convex hull in (a) is slightly lower than indicated by the corresponding compounds near $x/(x+y)=0.5$ because it includes additional new compounds found at a later search stage. The ZrSe compound (ZrS prototype) found in this stage is superseded at a later stage by a slightly more stable structure of the same composition (see Figure \ref{['fig:3']}).
• Figure 3: Near neighbors' enrichment, i.e., $A$S ($A$Se) structure types with $A$-elements from the same or adjacent columns. The orange triangles are the known ICSD compounds, the purple $x$-markers indicate the near-neighbor structures, and the green and cyan colors indicate $A$-elements from clusters in the periodic table that were found to be stoichiometry-rich in the sulfide and selenide binary systems Hever2017. The locations of the different $A$-atoms in the periodic table are marked by the corresponding colors in the inset in each frame.
• Figure 4: The convex hull of the TiS system enriched with structure types from all binary sulfide compounds $A_x$S$_y$. The six panels correspond to $A$-atoms from different regions of the periodic table. The red square in each legend marks the location of Ti in the periodic table and the blue region covers the corresponding replacement elements.
• Figure 5: The convex hull of the TaSe system. The notations are as in Figure \ref{['fig:4']}.