科研之友
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摘要
A first-principles investigation of cuprite crystals (Cu2O and Ag2O) has been performed. For Cu2O, the calculated frequencies at the Gamma point of the Brillouin zone are in very good agreement with the experimental frequencies. For Ag2O, the presence of E-u and F-2u vibrational modes with negative frequencies indicates a low temperature phase transition, in agreement with recent high resolution X-ray and neutron diffraction measurements. The energy scanning along these two modes shows a double-well potential, within which only the Ag atoms vibrate. As a result, the origin of the phase transition can be attributed to displacive disorder of the Ag atoms.
- 出版日期2011-10
