Abstract
This paper identifies the microscopic origin of breathing versus polar distortions exhibited by ABO3 perovskites, containing active A sites like Bi or Pb. The authors show that that the condition by which the system exhibits breathing type distortion manifested as alternating compressed and expanded AO12 polyhedra or polar distortion manifested as off-centric movement of A cations is determined by the energy positioning of O-2p within the 6s-6p energy window of A site.
Highlights
The physical properties [1] of transition metal (TM) perovskites of general formula ABO3, are believed to be dictated by the B-site TM d electrons and the O p electrons
A parallel almost exists between Bi and Pb compounds; PbCrO3 shows breathing distortion of alternate expansion and compression of PbO12 polyhedra [10], while compounds like PbVO3 or PbTiO3 show ferroelectric distortions [11,12]. We investigate this intriguing scenario within the framework of density functional theory (DFT), along with solution of model Hamiltonian, constructed based on DFT essentials
This tendency toward polar instability versus the breathing instability can be described within a common framework of A-site 6s and 6p orbitals hybridizing with O 2p orbitals
Summary
The physical properties [1] of transition metal (TM) perovskites of general formula ABO3, are believed to be dictated by the B-site TM d electrons and the O p electrons. A parallel almost exists between Bi and Pb compounds; PbCrO3 shows breathing distortion of alternate expansion and compression of PbO12 polyhedra [10], while compounds like PbVO3 or PbTiO3 show ferroelectric distortions [11,12] In this communication, we investigate this intriguing scenario within the framework of density functional theory (DFT), along with solution of model Hamiltonian, constructed based on DFT essentials. The trend of O 2p level position with respect to A-site 6s and 6p positions is demonstrated in terms of band centers, on site energies, Wannier functions, and crystal orbital Hamiltonian population, considering four compounds: BiFeO3, BiNiO3, PbVO3, and PbCrO3 This tendency toward polar instability versus the breathing instability can be described within a common framework of A-site 6s and 6p orbitals hybridizing with O 2p orbitals. Our study paves a way to understanding an important yet difficult problem which needs future attention
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
