Structure and dynamics in liquid bismuth and Bi(n) clusters: a density functional study

Area of Science:

• Condensed matter physics
• Computational materials science
• Physical chemistry

Background:

• Bismuth (Bi) exhibits unique electronic and structural properties due to its heavy nature.
• Understanding the liquid and cluster states of bismuth is crucial for its technological applications.

Purpose of the Study:

• To investigate the structural and dynamical properties of liquid bismuth and neutral Bi clusters.
• To compare the characteristics of liquid and cluster bismuth with its crystalline form.
• To explore the influence of temperature and spin-orbit coupling on bismuth's properties.

Main Methods:

• Density functional theory and molecular dynamics simulations were employed.
• Simulations were conducted on liquid bismuth at various temperatures (573–1023 K) and neutral Bi clusters (up to 14 atoms).
• Structural properties (coordination numbers, bond angles, structure factor, distribution functions) and dynamical properties (vibration frequencies, diffusion constants) were analyzed.

Main Results:

• Liquid bismuth and Bi clusters exhibit similar structural patterns, distinct from crystalline bismuth.
• Higher temperatures in liquid bismuth lead to increased void volume and local concentration variations.
• Spin-orbit coupling was found to reduce cohesive energies in Bi clusters by 0.3–0.5 eV/atom.

Conclusions:

• The study highlights the shared structural motifs between liquid and clustered bismuth.
• Temperature significantly impacts the local structure and homogeneity of liquid bismuth.
• Spin-orbit coupling plays a notable role in the energetic stability of bismuth clusters.