Recently the unusual cubic perovskite-related CaCu3-
Ti4O12 (CCTO) has attracted considerable attention and
been much studied because it possesses an extraordinarily
high dielectric constant at room temperature of about
104–105 and good temperature stability over a wide temperature
range from 100 to 600 K [1–3]. Both properties are
significant for device implementation. Although CCTO
possesses such a high permittivity, the intrinsic nature of
the polarization has been questioned and essentially is
inconsistent with the results based on first-principles calculations
[4,5]. Moreover, unlike the common ferroelectric
ceramics, no structural or ferroelectric transition has been
observed in CCTO over a wide temperature range [1,2