Lattice-mediated bulk flexoelectricity from first principles

First-principles theory of frozen-ion flexoelectricity

We demonstrate that the frozen-ion contribution to the flexoelectric coefficient is given solely in terms of the sum of third moments of the charge-density distortions induced by atomic displacements, even for ferroelectric or piezoelectric materials. We introduce several practical supercell-based methods for calculating these coefficients from first principles, and demonstrate them by computin...

The flexoelectricity of barium and strontium titanates from first principles.

We present ab initio calculations of the longitudinal flexoelectricity for BaTiO(3) and SrTiO(3) using a direct approach. The calculated value for SrTiO(3) agrees with recently reported measurements. For BaTiO(3), however, the theoretical values are smaller than the measured ones; possible reasons for the discrepancy are discussed.

First-principles approach to lattice-mediated magnetoelectric effects.

We present a first-principles scheme for the computation of the linear magnetoelectric response of magnetic insulators. We focus on the lattice-mediated part of the response, which we argue can be expected to be dominant in materials displaying strong magnetoelectric couplings. We apply our method to Cr2O3 and show that its low-temperature response has a significant lattice character.

Lattice dielectric response of CdCu3Ti4O12 and CaCu3Ti4O12 from first principles

Structural, vibrational, and lattice dielectric properties of CdCu3Ti4O12 are studied using the densityfunctional theory within the local spin-density approximation, and the results are compared with those computed previously for CaCu3Ti4O12 . Replacing Ca with Cd is found to leave many calculated quantities largely unaltered, although significant differences do emerge in zone-center optical ph...

Lattice dynamics of anharmonic solids from first principles