Related papers: Ferroelectricity in [111]-oriented epitaxially str…
The pyroelectric effect in ferroelectric thin films is typically composed of different contributions, which are difficult to disentangle. In addition, clamping to the substrate interface plays an important role. We studied epitaxial…
For the ferroelectric perovskite compounds BaTiO3 and PbTiO3, we have studied the effects of external electric fields on the structural properties of the (001) surfaces. The field-induced changes in the surface interlayer spacings and…
We have investigated the crystal structure and the ferroelectric properties of BaTiO3 thin films with YBa2Cu3O7-d as the bottom and Au as the top electrode. Epitaxial heterostructures of YBa2Cu3O7-d and BaTiO3 were prepared by dc and rf…
The ferroelectric property of BaTiO$_3$ crystal arises from the strong Pseudo Jahn-Teller (PJT) interactions between the non-degenerate ground electronic state, $^1A_{1g}$ and the degenerate $^1T_{1u}$ symmetry states through the nuclear…
Ferroelectricity in BaTiO3 was observed nearly eighty years ago, but the mechanism underlying its ferroelectric-paraelectric phase transition remains elusive. The order-disorder transition has been recognized as playing a critical role,…
Here a recently observed weak first order transition in doped SrTiO3 is argued to be a consequence of the coupling between strain and order parameter fluctuations. Starting with a semi-microscopic action, and using renormalization group…
Results from dielectric and structural measurements on epitaxial SrTiO$_3$/BaZrO$_3$ superlattices reveal properties that cannot be explained simply in terms of those measured on single films of the constituent materials. For large…
The ground-state structural and electronic properties of ferroelectric BiFeO$_3$ are calculated using density functional theory within the local spin-density approximation and the LSDA+U method. The crystal structure is computed to be…
We present a first-principles study of 180-degree ferroelectric domain walls in tetragonal barium titanate. The theory is based on an effective Hamiltonian that has previously been determined from first-principles ultrasoft-pseudopotential…
The spontaneous polarization of epitaxial BaTiO$_3$/SrTiO$_3$ superlattices is studied as a function of composition using first-principles density functional theory within the local density approximation. With the in-plane lattice parameter…
Highly-crystalline ferroelectric oxides integrated on Si hold great promise for energy-efficient memory and logic technologies. Exploiting epitaxial strain engineering in these materials is, however, severely hampered on Si, where the large…
Multiferroic BiFeO$_3$ (BFO) possesses a rich phase diagram that allows strain tuning of its properties in thin-film form. In particular, at large compressive strain, a supertetragonal (T) phase with giant polarization is stabilized over…
The structure, polarization, and zone-center phonons of bulk tetragonal BaTiO$_3$ under compressive epitaxial stress are calculated using density functional theory within the local density approximation. The polarization, computed using the…
We review the role that first-principles calculations have played in understanding the effects of substrate-imposed misfit strain on epitaxially grown perovskite ferroelectric films. We do so by analyzing the case of BaTiO$_3$,…
An effective Hamiltonian for the ferroelectric transition in $PbTiO_3$ is constructed from first-principles density-functional-theory total-energy and linear-response calculations through the use of a localized, symmetrized basis set of…
An atomistic effective Hamiltonian technique is used to investigate the finite-temperature energy storage properties of a ferroelectric nanocomposite consisting of an array of BaTiO$_{3}$ nanowires embedded in a SrTiO$_{3}$ matrix, for…
Ferroelectric materials such as BaTiO3 exhibit spontaneous polarization that can be reoriented by an external electric field, forming the basis of various memory, actuator, and sensor applications. The polarization switching behavior,…
Epitaxial strain has emerged as a powerful tool to tune magnetic and ferroelectric properties in functional materials such as in multiferroic perovskite oxides. Here, we use first-principles calculations to explore the evolution of magnetic…
The changes of polarizational, elastic and structural properties of mutiferroic BiFeO3 under [111] direction uniaxial stress are calculated using density functional theory within the Perdew-Burke- Ernzerhof revised for solids (PBEsol) + U…
In the framework of Landau--Ginzburg--Devonshire (LGD) phenomenological theory, the influence of misfit strains, surface energy, and finite-size effects on phase diagrams, polar properties, and hysteresis loops has been calculated for…