Displacive phase-transition of cuprite Ag2O revealed by extended x-ray absorption fine structure

• The low-temperature phase-transition of Ag2O has been investigated EXAFS spectroscopy.
• The temperature evolution of the local structure around Ag has been determined.
• A progressive splitting of the Ag–Ag next-nearest-neighbor distances is observed.
• The phase-transition of Ag2O can be attributed to displacive disorder of the Ag atoms.

The low-temperature phase-transition of silver oxide (Ag2O) has been investigated by extended x-ray absorption fine structure (EXAFS) spectroscopy as a function of temperature. The thermal evolution of the local structure around Ag atoms has been determined. In particular, below the phase-transition temperature at ∼35 K, a progressive splitting of the Ag–Ag next-nearest-neighbor distances is observed. This definitely supports the idea that the phase-transition of Ag2O is due to displacive disorder of the Ag atoms.