材料期刊网

The structural and electronic properties of R3c phase BiFeO(3) (111) surface were calculated by the full-potential augmented plane wave method within the LSDA + U. It is found that the (111)-Bi/O(3)/Feterminated surface is more stable than the O- and Fe-terminated surfaces at the O-poor environment, and (111)-O(3)/Fe/Bi-terminated surface is more stable than the Bi- and Fe-terminated surfaces at the O-rich environment. Indeed, the (111)-Fe/Bi/O(3)-terminated surface cannot be stabilized, after relaxation it will turn to the Bi-terminated surface. The density of states (DOS) of the relaxed BiFeO(3) (111) surface were calculated and compared with that of the bulk BiFeO(3). The ground-state electronic property of ferroelectric BiFeO(3) is found to be insulating and antiferromagnetic, but the BiFeO(3) (111) surface all have metallic properties, and the Fe magnetic moments are coupled ferromagnetically (F) within the pseudocubic (111) planes and antiferromagnetically (AF) between adjacent planes. (C) 2009 Elsevier B.V. All rights reserved.