Coarse-grained lattice dynamics calculations combined with independent stiffness approximation: a comparative study...

Area of Science:

• Solid-state physics
• Computational materials science
• Crystallography

Background:

• Lattice dynamics calculations are crucial for understanding material properties.
• Existing methods can be computationally expensive for complex crystal structures.
• Molecular vibration analysis offers a pathway to more efficient calculations.

Purpose of the Study:

• To adapt and apply a coarse-graining (CG) and independent stiffness approximation (ISA) method to polymorphs of p-dichlorobenzene.
• To enhance the applicability of theoretical frameworks to complex crystal structures by utilizing molecular symmetry.
• To investigate the impact of phonon mode coupling on frequency accuracy within a truncated CG space.

Main Methods:

• Application of a coarse-graining (CG) scheme combined with the independent stiffness approximation (ISA).
• Exploitation of molecular symmetry to reduce computational cost.
• Calculation of phonon band structures and thermodynamic functions for crystal polymorphs.

Main Results:

• Successful application of the CG-ISA method to p-dichlorobenzene polymorphs.
• Demonstration of reduced computational cost through the use of molecular symmetry.
• Obtained phonon band structures and thermodynamic functions showing structure-dependent differences.

Conclusions:

• The developed lattice dynamics approach is effective for analyzing crystal polymorphs.
• The method provides insights into subtle thermodynamic differences arising from crystal structure variations.
• This framework offers a computationally efficient route for studying complex crystalline materials.