High-pressure study of binary thorium compounds from first principles theory and comparisons with experiment

Area of Science:

• Materials Science
• Solid State Physics
• Computational Chemistry

Background:

• Binary thorium compounds (ThX) exhibit complex structural behaviors under pressure.
• Understanding these behaviors is crucial for developing new materials and applications.

Purpose of the Study:

• To investigate the high-pressure structural properties of ThX compounds (X = C, N, P, As, Sb, Bi, S, Se, Te).
• To determine structural phase transitions and stability under varying pressures.
• To explore the electronic structure of these compounds.

Main Methods:

• Utilized the all-electron full potential linear muffin-tin orbital (FP-LMTO) method with generalized gradient approximation (GGA).
• Employed the quasiparticle self-consistent GW method for electronic structure calculations.
• Performed new experiments for ThBi and ThN compounds.

Main Results:

• Calculated equilibrium lattice parameters, bulk moduli, and equations of state agree well with experimental data.
• Observed structural phase transitions from NaCl to CsCl type in ThP, ThAs, ThSb, and ThSe at specific high pressures.
• Identified stable structures for various ThX compounds below 50 GPa.

Conclusions:

• The study accurately predicts high-pressure structural behavior and phase transitions in binary thorium compounds.
• Computational methods provide reliable predictions for material properties under extreme conditions.
• Findings contribute to the fundamental understanding of thorium-based materials.