Electronic Ferroelectricity

Cristian D. Batista, LANL, T-11
Post-Doc Publication Award Winner

In 1894 Pierre Curie envisioned the possibility of controlling the electric polarization in a material by a magnetic field or inversely the magnetization by an electric field. It took until 1960 to find a compound exhibiting this important phenomenon named magneto-electric effect.

Textbook ferroelectric systems are ionic insulators whose properties are determined by the lattice degrees of freedom. However, a strong coupling between the ferroelectric and magnetic orders implies that the electronic degrees of freedom (the ones carrying a magnetic moment) can play a significant role in stabilizing the ferroelectric order. Therefore, I believe a complete theory of ferroelectricity must take the role of the electrons into account. In this talk, I will show that a ferroelectric state can be obtained just from the Coulomb electron-electron interaction, i.e., without involving the lattice degrees of freedom. We will also see that in this theory the coexistence of magnetic ordering and ferroelectricity emerges naturally from the strong interplay between the orbital and the spin degrees of freedom carried by each electron. This coexistence is the key to obtain a huge magneto-electric effect that would be of fundamental and applied significance.

The P/T Colloquium is
typically held each
Thursday, 3:45–5:00 PM.
Refreshments are served
at 3:15 PM.