Influence of the exchange and correlation functional on the structure of amorphous InSb and In3SbTe2 compounds

Area of Science:

• Materials Science
• Computational Materials Science
• Condensed Matter Physics

Background:

• Amorphous InSb and In3SbTe2 are promising for phase change non-volatile memory applications.
• Understanding their amorphous structure is crucial for optimizing device performance.

Purpose of the Study:

• Investigate the structural, vibrational, and electronic properties of amorphous InSb and In3SbTe2.
• Evaluate the impact of different exchange-correlation functionals on simulated amorphous structures.

Main Methods:

• Molecular dynamics simulations based on density functional theory (DFT).
• Quenching from the melt to generate amorphous phase models.
• Analysis of structural properties, focusing on atomic bonding geometries.

Main Results:

• The Becke-Lee-Yang-Parr (BLYP) functional resulted in a significantly higher fraction of tetrahedral In-bonding in amorphous InSb and In3SbTe2 compared to the Perdew-Becke-Ernzerhof (PBE) functional.
• This contrasts with Ge2Sb2Te5, where both functionals yield similar amorphous structures.
• The choice of exchange-correlation functional critically influences the simulated atomic structure.

Conclusions:

• The BLYP functional provides a more accurate representation of the amorphous InSb and In3SbTe2 structures, particularly regarding In atom coordination.
• This finding highlights the importance of functional selection in DFT simulations for phase change materials.
• Further research should consider the BLYP functional for accurate modeling of these compounds.