Details

Autor(en) / Beteiligte

• Gu, Teng
• Scarbrough, Timothy
• Yang, Yurong
• Íñiguez, Jorge
• Bellaiche, L
• Xiang, H J

Titel

Cooperative Couplings between Octahedral Rotations and Ferroelectricity in Perovskites and Related Materials

Ist Teil von

• Physical review letters, 2018-05, Vol.120 (19), p.197602-197602, Article 197602

Ort / Verlag

United States: American Physical Society

Erscheinungsjahr

2018

Quelle

American Physical Society

Beschreibungen/Notizen

• The structure of ABO_{3} perovskites is dominated by two types of unstable modes, namely, the oxygen octahedral rotation (AFD) and ferroelectric (FE) mode. It is generally believed that such AFD and FE modes tend to compete and suppress each other. Here we use first-principles methods to show that a dual nature of the FE-AFD coupling, which turns from competitive to cooperative as the AFD mode strengthens, occurs in numerous perovskite oxides. We provide a unified model of such a dual interaction by introducing novel high-order coupling terms and explain the atomistic origin of the resulting new form of ferroelectricity in terms of universal steric mechanisms. We also predict that such a novel form of ferroelectricity leads to atypical behaviors, such as an enhancement of all the three Cartesian components of the electric polarization under hydrostatic pressure and compressive epitaxial strain.