Dynamical coupling in Pb(Zr,Ti)O-3 solid solutions from first principles

作者：Wang Dawei^*; Weerasinghe Jeevaka; Bellaiche L; Hlinka Jirka

来源：Physical Review B, 2011, 83(2): 020301.

DOI：10.1103/PhysRevB.83.020301

A first-principles-based approach is developed to model dynamical coupling between different degrees of freedom in the terahertz frequency range at any temperature. Such an approach is applied to Pb(Zr,Ti)O-3 alloys, which exhibit both ferroelectric (FE) and antiferrodistortive (AFD) motions. It reproduces very well the existence of two modes (rather than the single E(1TO) soft mode) in the 50-75 cm(-1) range for temperatures smaller than similar or equal to 200 K. It also provides an insight into the existence of these two modes, which originate from the coupling between long-range-ordered FE and AFD motions. The proposed scheme is further used to reveal a field-induced anticrossing involving FE and AFD degrees of freedom.

• 出版日期2011-1-13