相关论文: From latent ferroelectricity to hyperferroelectric…

Halide perovskite semiconductors respond to electric fields in a way that varies across time and length scales. We discuss the microscopic processes that give rise to the macroscopic polarization of these materials, ranging from the optical…

Ferroelectricity is usually found in compound materials composed by different elements. Here, based on first-principles calculations, we reveal the first example of spontaneous electrical polarization and ferroelectricity in stable…

The stability of high-symmetry $P4mm$ polar phase in eleven ferroelectric perovskite superlattices with the polar discontinuity is studied from first principles. In most superlattices, this phase exhibits either the ferroelectric or the…

Dabconium hybrid perovskites include a number of recently-discovered ferroelectric phases with large spontaneous polarisations. The origin of ferroelectric response has been rationalised in general terms in the context of hydrogen bonding,…

A wide variety of applications has inspired great interest in designing new materials and investigating fundamental physics in the ferroelectric field. In the concept of ferroelectricity, the spontaneous polarization is traditionally…

Methylammonium lead iodide, as related organometal halide perovskites, emerged recently as a particularly attractive material for photovoltaic applications. The origin of its appealing properties is sometimes assigned to its potential…

Thin films of aluminum hafnium nitride (Al$_{1-x}$Hf$_{x}$N) were synthesized via reactive magnetron sputtering for Hf contents up to $x$ = 0.13. X-ray diffraction showed a single $c$-axis oriented wurtzite phase for all films. Hard X-ray…

All known proper ferroelectrics are unable to polarize normal to a surface or interface if the resulting depolarization field is unscreened, but there is no fundamental principle that enforces this behavior. In this work, we introduce…

The stability of a high-symmetry $P4mm$ polar phase in seventeen short-period ferroelectric perovskite superlattices with polar discontinuity is studied from first principles within the density-functional theory. It is shown that in most…

Lead halide perovskites have been extensively studied as a class of materials with unique optoelectronic properties. A fundamental aspect that governs optical and electronic behaviors within these materials is the intricate coupling between…

Recently ferroelectricity has been demonstrated in the family of halide perovskites: CsGeX$_3$ (X=Cl, Br, I). We develop a first-principles-based computational approach to probe finite-temperature properties of \cgb. Our computations reveal…

The ferroelectric polarization of perovskite oxides is much larger than implied by displacement of static ionic charges. We use an explicitly correlated scheme to investigate the phenomenon; charge transport is evaluated as a geometric…

The (001) surfaces of polar perovskites BaTiO$_3$ and PbTiO$_3$ have been studied from first principles at T=0 K. For both cases of polarization, the most stable TiO-terminated interfaces show intrinsic ferroelectricity. In the topmost…

We show the first-principles evidence of a hitherto unreported type of ferroelectricity with ultra-long ion-displacement in sodium and potassium hydroxides. Even a small amount of proton vacancies can completely change the mode of…

We present a phenomenological model of periodic ferroelectric-superconductor (FE-S) heterostructures containing two alternating ferroelectric and superconducting layers. The interaction at the FE-S contacts is described as a coupling of the…

Advances in first-principles computational approaches have, over the past fifteen years, made possible the investigation of physical properties of ferroelectric systems. In particular, such approaches have led to a microscopic understanding…

There are two silver perovskite oxides: AgNbO3 and AgTaO3. AgNbO3 has a noncentrosymmetric group of Pmc21 at room temperature with a ferri-electric ordering of polarization. Such a ferri-electric state with small polarization can be changed…

Halide perovskites have emerged as promising materials for next-generation photovoltaics, laser sources and X-ray detectors. There is intense debate as to whether some photoactive halide perovskites exhibit ferroelectric behaviour and…

We present a perspective on recent observations of the photoinduced phase separation of halides in multi-component lead-halide perovskites. The spontaneous phase separation of an initial homogeneous solid solution under steady-state…

From lithium-ion batteries to high-temperature superconductors, oxide materials have been widely used in electronic devices. However, demands of future technologies require materials beyond oxides, as anion chemistries distinct from oxygen…