Surface effects on the crystallization kinetics of amorphous antimony

Area of Science:

• Materials Science
• Computational Materials Science
• Condensed Matter Physics

Background:

• Elemental antimony (Sb) is a key material for advanced electronics like phase-change memory and neuro-inspired computing.
• Amorphous Sb is desirable for these applications due to its stability, but the reasons for its stability in thin films without capping layers were unclear.
• Previous studies explained stability due to capping or confinement, but not the role of free surfaces.

Purpose of the Study:

• To investigate the effect of free surfaces on the crystallization kinetics of amorphous antimony (Sb) thin films.
• To elucidate the fundamental mechanisms behind the enhanced stability of amorphous Sb in thin-film devices.

Main Methods:

• Utilized ab initio molecular dynamics (AIMD) simulations.
• Compared crystallization behavior of bulk and surface models of amorphous Sb at 450 K.

Main Results:

• Observed distinct crystallization behaviors between bulk and surface models.
• Identified a sub-nanometer surface region where crystallization is intrinsically suppressed.
• Demonstrated that free surfaces impede the incubation process and confine nucleation to two dimensions.

Conclusions:

• Free surfaces play a critical role in stabilizing amorphous Sb thin films by creating a surface-induced amorphous layer.
• This surface effect is essential for understanding and improving the reliability of Sb-based thin-film memory devices.
• The findings provide insights into designing more stable amorphous materials for future electronic applications.