title: First principles simulation of temperature dependent electronic transition of FM-AFM phase BFO.
abstract: 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 (50~1500 K). The results suggest that the heat accumulation accelerates the O-2p(4) orbital splitting, inducing the Fe(3+)-3d(5) → Fe(2+)-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 Fe(3+)-3d(5), in comparison to the O → Bi-6p(3) + Fe(3+)-3d(5)d(0) on the orientations (001) and (101). This study offers new perspective on the improvement of BFO-based temperature-sensitive device.
authors: Xinjiang Key Laboratory of Electronic Information Materials and Devices, CAS, Urumqi, 830011, Xinjiang, China, bianliang@ms.xjb.ac.cn.
authors: Liang
authors: L
authors: Bian
authors: Jin-bao
authors: JB
authors: Xu
authors: Mian-xin
authors: MX
authors: Song
authors: Fa-qin
authors: FQ
authors: Dong
authors: Hai-liang
authors: HL
authors: Dong
authors: Fa-Nian
authors: FN
authors: Shi
authors: Xiao-Yan
authors: XY
authors: Zhang
authors: Tao
authors: T
authors: Duan