Atomic and electronic structure transformations in SnS2 at high pressures: a joint single crystal X-ray diffraction...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Layered semiconductors like tin disulfide (SnS2) are crucial for intercalation and optoelectronic applications.
• The precise structure-property relationships in metal dichalcogenides, including SnS2, remain incompletely understood.
• Understanding these relationships is key to optimizing material performance.

Purpose of the Study:

• To investigate the pressure-dependent structural and electronic properties of single-crystal SnS2.
• To elucidate the role of interlayer interactions in the compression mechanism of SnS2.
• To explore the potential for tuning SnS2's electronic properties via pressure.

Main Methods:

• Single-crystal X-ray diffraction was employed to analyze structural changes under pressure (0-20 GPa).
• Density Functional Theory (DFT) calculations were used to model electronic band structure and predict property changes.
• Optical color changes of the single crystal were observed to correlate with electronic transitions.

Main Results:

• SnS2 exhibits anisotropic compression, primarily driven by changes in the van der Waals interlayer distance.
• Compression significantly enhances S···S interlayer interactions, distinct from other MS2 compounds.
• DFT calculations show a pressure-induced narrowing of the band gap, from 2.15 eV at ambient pressure to 0.88 eV at 20 GPa.
• A reversible color change in the crystal confirms the band gap modification.

Conclusions:

• SnS2 displays unique compression characteristics within the metal dichalcogenide family, governed by interlayer forces.
• Pressure-induced electronic structure modifications, including band gap reduction, are clearly demonstrated.
• Band gap closure is predicted around 33 GPa, suggesting potential for pressure-tuned electronic devices.