A generalized solid-state nudged elastic band method.

Area of Science:

• Materials Science
• Computational Chemistry
• Solid-State Physics

Background:

• Solid-solid phase transitions are crucial in materials science.
• Accurately predicting transformation pathways is computationally challenging.
• Existing methods often struggle to incorporate both atomic and unit-cell dynamics.

Purpose of the Study:

• To introduce a generalized solid-state nudged elastic band (G-SSNEB) method.
• To enable robust calculation of reaction pathways for solid-solid transformations.
• To develop a method insensitive to the choice of periodic cell.

Main Methods:

• Unified description of crystal structure combining atomic and cell degrees of freedom.
• Application of the G-SSNEB method to the rock-salt to wurtzite transition in CdSe.
• Utilizing density functional theory for force and stress tensor calculations.

Main Results:

• The G-SSNEB method is robust for mechanisms driven by atomic motion or unit-cell deformation.
• Demonstrated a size-dependent transition mechanism in CdSe.
• Observed a shift from concerted transformation in small cells to nucleation in large cells.

Conclusions:

• The G-SSNEB method provides an efficient and versatile approach for studying solid-state transformations.
• The findings highlight the importance of considering cell size effects on phase transition mechanisms.
• This method can be applied to various systems using first-principles calculations.