Local structural distortions in SnTe investigated by EXAFS

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Tin telluride (SnTe) exhibits a ferroelectric transition.
• Understanding local structural dynamics is crucial for materials properties.

Purpose of the Study:

• To investigate the local structure and phase transitions in SnTe using EXAFS.
• To determine the temperature dependence of structural distortions.

Main Methods:

• Extended X-ray Absorption Fine Structure (EXAFS) measurements at the Sn K-edge.
• Data analysis across a wide temperature range (5–480 K).

Main Results:

• Observed local rhombohedral distortion in SnTe from 5 K to 300 K.
• EXAFS data suggest a partial order-disorder character of the ferroelectric transition.
• Anomalous behavior of EXAFS cumulants above 300 K indicates modified anharmonicity.

Conclusions:

• The ferroelectric transition in SnTe has characteristics of both displacive and order-disorder types.
• Above 300 K, SnTe may undergo phase transitions or exhibit softening of high-frequency modes.