Spin-orbital-lattice entangled states in cubic d1 double perovskites
Abstract
The magnetism of cubic 4/5d1 double perovskites has been intensively investigated due to their geometrical frustration and multipolar exchange interaction, whereas many puzzling phenomena related to the lattice degrees of freedom, e.g. ``violation of the JT theorem'' in structural data and ``breaking of local point symmetry'' accompanying the ferromagnetic order, have not been understood. In this work, the interplay of spin-orbit coupling and vibronic coupling on the heavy d1 site is investigated by ab initio calculations. The stabilization energy of spin-orbital-lattice entangled states is found to be comparable to or larger than the exchange interactions, suggesting the presence of nonadiabatic Jahn-Teller dynamics in the systems. The entanglement of the spin and lattice degrees of freedom induces a strong magnetoelastic response. This multiferroic effect is at the origin of the recently reported breaking of local point symmetry accompanying the development of magnetic ordering in Ba2NaOsO6.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- 2019
- Bibcode:
- 2019APS..MART70192I