Abstract
The electronic and structural properties of LiBO3 (B = V, Nb, Ta, Os) are investigated via first-principles methods. We show that LiBO3 belong to the recently proposed hyperferroelectrics (hyperFEs), i.e., they all have unstable longitudinal optic phonon modes. Especially, the ferroelectric-like instability in the metal LiOsO3, whose optical dielectric constant goes to infinity, is a limiting case of hyperFEs. Via an effective Hamiltonian, we further show that, in contrast to normal proper ferroelectricity, in which the ferroelectric instability usually comes from long-range coulomb interactions, the hyperFE instability is due to the structure instability driven by short-range interactions. This could happen in systems with large ion size mismatches, which therefore provides a useful guidance in searching for novel hyperFEs.
Highlights
The electronic and structural properties of LiBO3 (B = V, Nb, Ta, Os) are investigated via first-principles methods
We show that LiBO3 belong to the recently proposed hyperferroelectrics, i.e., they all have unstable longitudinal optic phonon modes
Via an effective Hamiltonian, we further show that, in contrast to normal proper ferroelectricity, in which the ferroelectric instability usually comes from long-range coulomb interactions, the hyperFE instability is due to the structure instability driven by short-range interactions
Summary
Via an effective Hamiltonian, we further show that, in contrast to normal proper ferroelectricity, in which the ferroelectric instability usually comes from long-range coulomb interactions, the hyperFE instability is due to the structure instability driven by short-range interactions This could happen in systems with large ion size mismatches, which provides a useful guidance in searching for novel hyperFEs. The switchable polarization of ferroelectrics (FEs) made them an important class of materials for modern device applications. In a seminal work[4], Garrity, Rabe and Vanderbilt (GRV) showed that a class of recently discovered hexagonal ABC semiconducting FEs5 have very robust polarization properties even when the depolarization field is unscreened They can remain polarized down to single atomic layers when interfaced with normal insulators, and are given the name of hyperferroelectrics (hyperFEs). We show that LiBO3 are hyperFEs, and there are two co-existing and yet www.nature.com/scientificreports/
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