BaGe₈As₁₄: a semiconducting sodalite-type compound

Area of Science:

• Solid-state chemistry
• Materials science
• Crystallography

Background:

• Sodalite-type compounds are known for their diverse structures and potential applications.
• Germanate arsenides are less explored but offer unique bonding and electronic characteristics.

Purpose of the Study:

• To synthesize and characterize a novel sodalite-type barium germanate arsenide compound.
• To investigate the structural and electronic properties of BaGe8As14 for potential applications.

Main Methods:

• Solid-state synthesis.
• Single crystal X-ray diffraction for structural determination.
• Electrical property measurements (resistivity, carrier concentration).

Main Results:

• Successful synthesis of BaGe8As14 with a sodalite-type structure (space group I4[combining macron]3m).
• Discovery of vertex-sharing GeAs4 tetrahedra forming β-cages with disordered Ba atoms.
• Observed narrow bandgap (0.43 eV), low resistivity (2 × 10⁻² Ω cm), and high carrier concentration (1.6 × 10²⁰ cm⁻³).

Conclusions:

• BaGe8As14 exhibits a novel sodalite-type structure with potential for unique properties.
• The determined electronic properties indicate suitability as a candidate thermoelectric material.