resumo
Understanding how temperature affects the electronic transitions of BFO is important for design of BiFeO3 (BFO)-based temperature-sensitive device. Hitherto, however, there have been only very limited reports of the quantitative simulation. Here, we used density functional theory (DFT) and two-dimensional correlation analysis (2D-CA) techniques to calculate the systematic variations in electronic transitions of BFO crystal, over a range of temperature (50 similar to 1500 K). The results suggest that the heat accumulation accelerates the O-2p(4) orbital splitting, inducing the Fe3+-3d(5) -> Fe2+-3d(5)d(0) charge disproportionation. The origin is observed as the temperature-dependent electron transfer process changes from threefold degeneracy to twofold degeneracy. Additionally, the crystallographic orientation (111) can be used to control the 2p-hole-induced electronic transition as O -> unoccupied Fe3+-3d(5), in comparison to the O -> Bi-6p(3)+ Fe3+-3d(5)d(0) on the orientations (001) and (101). This study offers new perspective on the improvement of BFO-based temperature-sensitive device.
palavras-chave
MULTIFERROIC BIFEO3; ROOM-TEMPERATURE; MAGNETIC-PROPERTIES; NANOPARTICLES; FILMS; 1ST-PRINCIPLES; POLARIZATION; DYNAMICS
categoria
Biochemistry & Molecular Biology; Biophysics; Chemistry; Computer Science
autores
Bian, L; Xu, JB; Song, MX; Dong, FQ; Dong, HL; Shi, FN; Zhang, XY; Duan, T
nossos autores
Fa-Nian Shi
InvestigadorGrupos
agradecimentos
The authors acknowledge the financial supports by National Natural Science Foundation of China (41302029, 41130746, 41302027, and 41272050), International Technology Cooperation Foundation of Autonomous Region (20136009), West Light Foundation of The Chinese Academy of Sciences (RCPY201206), Key Fund Project of Sichuan Provincial (13ZA0163 and 2012JYZ002), Science and Technology Program of Urumqi (Y131020006), and Fundamental Science on Nuclear Waste and Environmental Security Laboratory (12zxnp05).