Charge Ordering and Ferroelectricity in Half-doped Manganites

Abstract

By means of density-functional simulations for half-doped manganites, such as pseudocubic Pr0.5Ca0.5MnO3 and bilayer PrCa2Mn2O7, we discuss the occurrence of ferroelectricity and we explore its crucial relation to the crystal structure and to peculiar charge/spin/orbital ordering effects. In pseudocubic Pr0.5Ca0.5MnO3, ferroelectricity is induced in the Zener polaron type structure, where Mn ions are dimerized. In marked contrast, in bilayer PrCa2Mn2O7, it is the displacements of apical oxygens bonded to either Mn3+ or Mn4+ ions that play a key role in the rising of ferroelectricity. Importantly, local dipoles due to apical oxygens are also intimately linked to charge and orbital ordering patterns in MnO2 planes, which in turn contribute to polarization. Finally, an important outcome of our work consists in proposing Born effective charges as a valid mean to quantify charge disproportionation effects, in terms of anisotropy and size of electronic clouds around Mn ions.

5 pages, 2 figures, submitted for publication

References in corpus (2)

• New phase transition in $P{r}_{1-x}C{a}_{x}Mn{O}_3$ system: evidence for electrical polarization in charge ordered manganites
• Lattice-form dependent orbital shape and charge disproportionation in charge- and orbital-ordered manganites

Cited by in corpus (9)

• Topology of crystalline insulators and superconductors
• Direct experimental evidence of multiferroicity in a nanocrystalline Zener polaron ordered manganite
• Fingerprints of spin-orbital polarons and of their disorder in the photoemission spectra of doped Mott insulators with orbital degeneracy
• Spin excitations used to probe the nature of the exchange coupling in the magnetically ordered ground state of Pr${}_{0.5}$Ca${}_{0.5}$MnO${}_3$
• Superlattice-induced ferroelectricity in charge-ordered La${}_{1/3}$Sr${}_{2/3}$FeO${}_3$
• Antiferromagnetic rare region effect in $P{r}_{0.5}C{a}_{0.5}Mn{O}_3$
• Electron-lattice coupling contributions to polarization switching in charge-order-induced ferroelectrics
• Coupled structural distortions, domains, and control of phase competition in polar SmBaMn${}_2$O${}_6$
• Magnetic structures and phase transitions of A-site Ordered Double-Perovskite SmBaMn2O6