,Orbital Hybridization of the Ferroelectric Rb2Cd2 (SO4)3: Origin of Domain Walls

• 作 者: DUAN Yi-Feng YI Lin
• 机 构: Department of Physics and State Key Laboratory of Laser Technology, Huazhong University of Science a
• 出 处: 中国物理快报（英文版）
• 发表日期: 2005年2期

We perform first-principle calculations for the study of the orthorhombic Rb2Cd2 (SO4)3 structure. Electronic energy bands, total and partial densities of states are reported and analysed. It is found that oxygen atomic 2p electrons strongly hybridize with Rb/or Cd 4d and S 2p states, resulting in two-type ionic groups with weak couplings. It is shown that macroscopic domain walls originate from such weak-coupling ionic groups, arising at the cell boundaries. The asymmetric cation bonds (Rb-O and Cd-O) and the subsequent rotations of the SO4tetrahedra can lead to the driving force of the ferroelectric behaviour. The predicted pyroelectric current effects are observed experimentally in the ferroelectric phase.