Ion Transport and High Frequency Dielectric of the Hollandite Nax(Ti<SUB>8-x</SUB>Cr<SUB>x</SUB>)O₁？ = Hollandite Nax(Ti<SUB>8-x</SUB>Cr<SUB>x</SUB>)O₁？의 이온 전송과 고유전율

다국어 초록 (Multilingual Abstract)

The Velocity Autocorrelation Function (VAF) of the sodium ions is calculated for a range of temperature from 250K to 1000K and converted into the linear ac-conductivity and ac-susceptibility response via Fourier transformation. A peak is found in the conductivity around 6×10¹² ㎐ that has some of the character of a Poley absorption. Here it is shown to be due to an harmonically coupled site vibrations of the sodium atoms. which extend only over a limited range. At frequencies below the peak the conductivity tends towards a constant i.e. dc value corresponding to a constant flow of ions through the simulation cell. At high temperatures the conductivity due to this ion transport process behaves like a metal with an insulator to metal transition occurring around a specific temperature.