Asymmetric covalence bonding between In 5s and O 2p states in ferroelectric InFeO3. (November 2018)

• Record Type: Journal Article
• Authors: Liu, Shanshan; Wang, Runxue; Wang, Cuihong; Wang, Fan; Xu, Yuanhui; Sun, Keju; Hao, Xianfeng
• Is Part Of: Journal of physics and chemistry of solids. Volume 122(2018)
• Page Start: 1
• Page End: 7
• Publication Date: 2018-11
• Subjects: First principles study -- InFeO3 -- Phase transition -- Ferroelectric properties -- PACS numbers: 71.15.Mb -- 64.70.Kb, 75.47.Lx -- 77.80.−e; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2018.06.009
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: The structural evolution, electronic and magnetic properties of the high-pressure nonpolar orthorhombic phase (orthorhombic, space group Pnma ) and the LiNbO3 -type (rhombohedral, space group R3c ) InFeO3 have been explored via first-principles calculations. Furthermore, the ferroelectric properties of the LiNbO3 -type phase have been revisited thoroughly. First of all, the nonpolar orthorhombic phase crystallized within Pnma space group was theoretically recognized. Secondly, the results reasonably reproduced the pressure-induced R3c → Pnma structural phase transition, which is in fair agreement with the experimental observation that the LiNbO3 -type phase can be achieved from the decompression of the high pressure perovskite phase. In addition, the electric polarization for the non-centrosymmetric LiNbO3 -type within the G-type antiferromagnetic ground state is evaluated to be 86.5 μC/cm 2 by means of the Berry phase formula. More interestingly, in conjunction with the geometric factor, an additional mechanism behind the ferroelectric displacement is clarified as the strong chemical bonding between the In 5s and O 2p orbitals, i.e., the hidden tendency to create space for the unoccupied antibonding states, independent of whether the cation is an s 0 or s 2 configuration, and is manifested in terms of the analysis of Born effective charges, potential energy surfaces, charge density isosurfaces. Graphical abstract: Image 1 Highlights: Nonpolar orthorhombic to LiNbO3 -type transition of InFeO3 has been confirmed. The polarization of LiNbO3 -type InFeO3 has been determined via Berry phase method. Besides geometric effect, In 5s-O 2p covalent interaction has been clarified for the origin of ferroelectric displacements.