Synopsis: Finding Ferroelectrics

First-principles calculations predict a new class of ferroelectrics.
Synopsis figure
J. W. Bennett et al., Phys. Rev. Lett. (2012)

Ferroelectrics exhibit a spontaneous electric polarization that can be reversed by an applied electric field, in the same way that a ferromagnet’s spontaneous magnetic moment can be reversed by a magnetic field. In pursuit of new materials with better properties than those currently available, Joseph Bennett at Rutgers University, New Jersey, and colleagues have investigated a class of materials that they predict will be ferroelectric.

Any insulating material with a polar structure can, in principle, be ferroelectric if the energy barrier for switching electric polarization is low enough. Following this idea, the team decided to study compounds of the LiGaGe structure type—a hexagonal structure that is “stuffed” with a cation lying between atomic planes. This structure is polar due to buckling of the planes, with atomic composition and the size of the “stuffing” ion controlling the degree of buckling and the energy barrier to switching electric polarization.

Most compounds having the LiGaGe structure belong to one of six common types, comprising combinations of elements from different atomic groups of the periodic table. Bennett et al. analyzed 18 existing non-rare-earth compounds and 70 hypothetical compounds that have never been synthesized. Through first-principles calculations, they showed that eight of the candidates have polarizations and barriers to switching comparable to or better than the paradigm ferroelectrics barium titanate (BaTiO3) and lead titanate (PbTiO3). Out of these eight candidates, six have previously been synthesized, and the other two, while so far hypothetical, could possibly be obtained in metastable phases. These results suggest the possibility of expanding the list of known ferroelectrics. – Daniel Ucko


More Features »


More Announcements »

Subject Areas

Semiconductor PhysicsMaterials Science

Previous Synopsis

Next Synopsis


Tiny Tractor Beam

Read More »

Related Articles

Synopsis: Quantum Circulator on a Chip
Quantum Information

Synopsis: Quantum Circulator on a Chip

A circulator that routes microwave signals is suitable for scaling up quantum-computing architectures. Read More »

Synopsis: Golden Mystery Solved
Materials Science

Synopsis: Golden Mystery Solved

A long-standing discrepancy between experiments and theory concerning the electronic properties of gold has now been resolved. Read More »

Synopsis: Flip-Flopping the Bands

Synopsis: Flip-Flopping the Bands

A pair of semiconductor quantum wells with an inverted band structure hosts electrons whose spins are almost all in the same quantum state.   Read More »

More Articles