Dielectric Behavior as a Screen in Rational Searches for Electronic Materials: Metal Pnictide Sulfosalts

Area of Science:

• Materials Science
• Solid State Physics
• Semiconductor Physics

Background:

• Dielectric screening is crucial for semiconductor performance, mitigating carrier scattering and trapping by defects, as seen in halide perovskites.
• However, dielectric properties are underutilized as a primary screening criterion for discovering novel electronic semiconductor materials.
• Metal-pnictide ternary sulfosalts, particularly those with Bi or Sb, represent a largely unexplored class of materials.

Purpose of the Study:

• To investigate the potential of using dielectric properties as a screening tool for identifying new electronic semiconductor materials.
• To explore metal-pnictide ternary sulfosalts containing Bi or Sb for their electronic and thermoelectric properties.
• To establish a chemical rule correlating crystal structure with high dielectric constants in these materials.

Main Methods:

• Conducted a materials search focusing on dielectric properties within the metal-pnictide ternary sulfosalt family.
• Analyzed electronic band structures to identify cross-gap hybridization and calculate Born effective charges.
• Investigated structure-property relationships, specifically the role of pnictogen-chalcogen bonding in determining dielectric constants.
• Evaluated compounds for low effective mass, high dielectric constant, and thermoelectric potential.

Main Results:

• Identified significant cross-gap hybridization in many metal-pnictide ternary sulfosalts, leading to enhanced Born effective charges and dielectric constants.
• Established a chemical rule linking pnictogen-chalcogen bond connectivity to high dielectric constants.
• Discovered several compounds exhibiting a combination of low effective mass and high dielectric constant, indicating suitability for electronic applications.
• Identified promising candidates for thermoelectric materials.
• Experimental data for Sn-Sb-S samples confirmed predicted good performance in optical properties and solar conversion efficiency.

Conclusions:

• Dielectric properties serve as a highly effective screening parameter for the discovery of complex semiconductors.
• Metal-pnictide ternary sulfosalts are a promising class of materials for electronic and thermoelectric applications.
• The established chemical rule provides a predictive framework for designing materials with enhanced dielectric properties.