Metastability relationship between two- and three-dimensional crystal structures: a case study of the Cu-based...

Area of Science:

• Materials Science
• Computational Materials Design
• Crystallography

Background:

• Three-dimensional (3D) crystal structures can be formed by stacking two-dimensional (2D) layers.
• Investigating 2D layer building blocks for 3D structures is crucial for computational materials design.

Purpose of the Study:

• To theoretically investigate the dynamical stability of copper-based compounds (CuX) in various crystal structures.
• To determine if the concept of using 2D layers as building blocks applies to computational materials design.

Main Methods:

• Theoretical investigation of dynamical stability.
• Molecular dynamics simulations.
• Tetragonal Bain path calculations.

Main Results:

• Copper-based compounds (CuX) in B[Formula: see text] and L1[Formula: see text] structures are dynamically stable if the buckled honeycomb (BHC) precursor is stable.
• CuAu in B[Formula: see text] and L1[Formula: see text] structures exhibit stability up to 1000 K.
• A clear interrelationship between buckled square (BSQ) metastability and 3D structures (B2, L1[Formula: see text]) was not found; however, stability in B2 implies instability in L1[Formula: see text], and vice versa.

Conclusions:

• The geometric concept of using 2D layers as building blocks is applicable to designing stable 3D copper-based materials.
• The stability of derived 3D structures is directly linked to the stability of their 2D precursors (BHC).
• The stability relationship between B2 and L1[Formula: see text] structures is inversely correlated, as evidenced by tetragonal Bain path calculations.