Shape-induced phase transition of vortex domain structures in ferroelectric nanodots and their controllability by electrical and mechanical loads

摘要

Shape-induced phase transition of vortex domain structures (VDSs) in BaTiO3 (BT) nanodots under open circuit boundary condition have been investigated using an effective Hamiltonian method.Our calculation indicates the tetragonal VDS missing in cubic BT nanodots can be induced by varying the shape of a nanodot from cube to platelet.Interestingly,a novel VDS is found in BT nanoplatelets in our simulations.Further investigation shows that it is a result of compromise between the ground state and the symmetry of the shape of the nanodot.Furthermore,based on the novel VDS,routes of controlling VDSs governed by homogeneous electric field and uniform stress are discussed.In particular,our results show the possibility of designing multi-states devices based on a single VDS.