Abstract
We demonstrate, using a combination of experiment and density functional theory, that orbital ordering drives the formation of a one-dimensional (1D) antiferromagnetic spin chain in the 3D rocksalt structure of cesium superoxide (). The magnetic superoxide anion () exhibits degeneracy of its -derived molecular orbitals, which is lifted by a structural distortion on cooling. A spin chain is then formed by zigzag ordering of the half-filled superoxide orbitals, promoting a superexchange pathway mediated by the orbitals of along only one crystal direction. This scenario is analogous to the -orbital-driven spin chain found in the perovskite and is the first example of an inorganic quantum spin system with unpaired electrons.
- Received 13 February 2012
DOI:https://doi.org/10.1103/PhysRevLett.108.217206
© 2012 American Physical Society