相关论文: First principles-based calculation of the electroc…
An effective Hamiltonian for the ferroelectric transition in PbTiO3 is constructed from first-principles density-functional-theory total-energy and linear-response calculations through the use of a localized, symmetrized basis set of…
The phase-transition sequence of a ferroelectric perovskite such as BaTiO_3 can be simulated by computing the statistical mechanics of a first-principles derived effective Hamiltonian [Zhong, Vanderbilt and Rabe, Phys. Rev. Lett. 73, 1861…
We report the discovery of serendipitous electrocaloric effects in commercial multilayer capacitors based on ferroelectric BaTiO3. Direct thermometry records ~0.5 K changes due to 300 kV cm-1, over a wide range of temperatures near and…
The adiabatic temperature change ($\Delta T_{ad}$) of a magnetic refrigerant can be indirectly estimated through field ($H$) and temperature ($T$) dependent magnetization ($M$) and specific heat ($C_p$) measurements. A direct integration…
The first-principles-based effective Hamiltonian scheme provides one of the most accurate modeling technique for large-scale structures, especially for ferroelectrics. However, the parameterization of the effective Hamiltonian is…
We report on the dielectric and electrocaloric properties of Ba$_{1-y}$Ca$_y$Ti$_{1-x}$Hf$_x$O$_3$ for compositions $0.12<x<0.18$ and $y=0.06$, as well as $x=0.15$ and $0<y<0.15$, synthesized by the conventional solid-state reaction method.…
A method for the calculation of the temperature dependence of dielectric and piezoelectric responses, based on the use of a first-principles effective Hamiltonian, is described. Results are presented for the ferroelectric perovskite PbTiO3.…
Ab initio techniques have revolutionised the way in which theory can help practitioners to explore critical mechanisms that govern reactions or properties, and to develop new strategies for materials discovery and design. Yet, their…
Accurately predicting the Curie temperature ($T_c$) of ferroelectrics from first principles remains a major challenge, as theoretical estimates often fall significantly below experimental values. In this work, we investigate the origin of…
A quantitative discussion of nonperturbative effects for the high temperature electroweak phase transition is presented. We propose a method for the computation of the temperature dependent effective scalar potential that takes into account…
Due to critical environmental issues there is a pressing need to switch from current refrigeration methods based on compression of greenhouse gases to novel solid-state cooling technologies. Solid-state cooling capitalizes on the thermal…
We present a semi-empirical effective Hamiltonian to capture effects of disorder associated with Ba and Sr cations occupying $A$ sites in (Ba$_{x}$Sr$_{1-x}$)TiO$_3$ on its ferroelectric phase transition. Averaging between the parameters of…
Due to its high energy efficiency and environmental friendliness, solid-state cooling based on the barocaloric (BC) effect represents a promising alternative to traditional refrigeration technologies relying on greenhouse gases. Plastic…
The exchange-driven contribution to the magnetoelectric susceptibility $\hat\alpha$ is formulated using a microscopic model Hamiltonian coupling the spin degrees of freedom to lattice displacements and electric field, which may be…
We investigate the temperature-pressure phase diagram of BaTiO_3 using a first-principles effective-Hamiltonian approach. We find that the zero-point motion of the ions affects the form of the phase diagram dramatically. Specifically, when…
A new simulation approach of field evaporation is presented. The model combines classical electrostatics with molecular dynamics (MD) simulations. Unlike previous atomic-level simulation approaches, our method does not rely on an…
Long-range electrostatic interactions critically affect polar materials. However, state-of-the-art atomistic potentials, such as neural networks or Gaussian approximation potentials employed in large-scale simulations, often neglect the…
Nonequilibrium electron dynamics in solids is an important subject from both fundamental and technological points of view. The recent development of laser technology has enabled us to study ultrafast electron dynamics in the time domain.…
La(Fe$_x$Si$_{1-x}$)$_{13}$ and derived quaternary compounds are well-known for their giant, tunable, magneto- and barocaloric responses around a first-order paramagnetic-ferromagnetic transition near room temperature with low hysteresis.…
We investigate the effect of epitaxial strain on the electrocaloric effect (ECE) in BaTiO$_3$ by means of ab initio based molecular dynamics simulations. We show that tensile strain can be used to optimize the operation range for ferroic…