相关论文: First-Principles Computations for KTN

The prototypical antiferroelectric PbZrO$_3$ has several unsettled questions, such as the nature of the antiferroelectric transition, possible intermediate phase and the microscopic origin of the Pbam ground state. Using first principles,…

In the context of the search for environment-respectful, lead- and bismuth- free chemical compounds for devices such as actuators, SnTiO3 (ST) is investigated from first principles within DFT. Full geometry optimization provides a stable…

We present an inexpensive first-principles approach for describing quantum paraelectricity that combines density functional theory (DFT) treatment of the electronic subsystem with quantum mechanical treatment of the ions through solution of…

We report the observation of a phase transition in a KTaO$_3$ crystal, corresponding to a paraelectric-to-ferroelectric transition. The crystal was placed inside a copper cavity to form a dielectric-loaded microwave cavity, and the…

This paper analyzes how the ferroelectric properties of cubic-like BiFeO$_3$ nanoparticles are affected by different terminations and charge distributions at the surface using ab-initio-based atomistic computational experiments. Our…

The structure of the ferroelectric phase of undoped KTiOPO$_4$ and its solid solutions with zirconium and niobium is studied from first principles within the density functional theory. The second-order nonlinear susceptibility tensor and…

The dynamic structures of the cubic and tetragonal phase in BaTiO3 and its dielectric response above the cubic-to-tetragonal phase transition temperature (Tp) are studied by first-principles molecular dynamics (MD) simulation. It's shown…

The accumulation of boron within the porous nickel ferrite (NiFe2O4, NFO) deposited on fuel rods is a major technological problem with important safety and economical implications. In this work the electronic structure of nickel ferrite is…

We discuss, within the context of first order perturbation theory, the correction to the NLO BFKL wavefuncyion for scattering processes with non-zero momentum transfer, arising from the fact that in NLO the kernel is not covariant under…

We present a detailed study of the structural behavior and polarization reversal mechanism in phase III of KNO$_3$, an unusual ferroelectric material in which the nitrate groups rotate during polarization reversal. This material was one of…

First principles calculations are used to investigate the effects of epitaxial strain on the structure of the perovskite oxide CaTiO$_3$, with particular focus on the stabilization of a ferroelectric phase related to a polar instability…

We describe implementation and analysis of a first-principles theory, derived in an earlier work, for the leading terms in an expansion of a Gibbs free energy of a multi-component alloy in terms of order parameters that characterize…

Theoretical {\em ab initio} and experimental methods were used to investigate the $x$Bi(Zn,Ti)O$_3$-(1-$x$)PbTiO$_3$ (BZT-PT) solid solution. We find that hybridization between Zn 4$p$ and O 2$p$ orbitals allows the formation of short,…

With the aim to get an insight in the origin of differences in the earlier reported calculation results for KNbO3 and to test the recently proposed implementation of the FP-LMTO method by Methfessel and van Schilfgaarde, we perform a…

First-principles calculations have been conducted to study the structural, vibrational and dielectric properties of {\beta}-Si3N4. Calculations of the zone-center optical-mode frequencies (including LO-TO splittings), Born effective charge…

We extend our previous first-principles theory for perovskite ferroelectric phase transitions to treat also antiferrodistortive phase transitions. Our approach involves construction of a model Hamiltonian from a Taylor expansion,…

We introduce a novel computational approach for the investigation of complex correlated electron materials which makes it possible to evaluate interatomic forces and thereby determine atomic displacements and structural transformations…

The phase diagram and equation of state of dense nitrogen are of interest in understanding the fundamental physics and chemistry under extreme conditions, including planetary processes, and in discovering new materials. We predict several…

Using first-principles calculations, we analyze the structural properties of tungsten trioxide WO3 . Our calculations rely on density functional theory and the use of the B1-WC hybrid functional, which provides very good agreement with…

We present a detailed quantum mechanical non empirical DFT investigation of the energy-optimized geometries, phase stabilities and electronic properties of bulk Pt3N, PtN and PtN2 in a set of twenty different crystal structures. Structural…