Abstract
By calculating the electronic, orbital, magnetic, and lattice structure of half-doped manganites we establish the central role of oxygen buckling caused by the tilting of the MnO octahedra, which is, in essence, a steric effect. The buckling itself does not change the Mn-Mn bonds. Instead, it drives the system toward an instability where these bonds can dimerize. In the presence of electron-electron interactions, this instability can fully develop, and beyond a critical buckling a Zener polaron ground state with dimerized spins, lattice, and orbitals forms spontaneously, resulting in a multiferroic state.
- Received 27 May 2011
DOI:https://doi.org/10.1103/PhysRevB.83.233103
©2011 American Physical Society