相关论文: Superstructure reflexions in tilted perovskites pa…

Despite the simplicity of the original perovskite crystal structure, this family of compounds shows an enormous variety of structural modifications and variants. In the following, we will describe several examples of perovskites, their…

Using first-principles methods, we predict the energy landscape and ferroelectric states of double perovskites of the form AA$'$BB$'$O$_6$ in which the atoms on both the A and B sites are arranged in rock-salt order. While we are not aware…

Voids can be observed at various scales in ductile materials, frequently of sizes lower than the grain size, leading to porous single crystals materials. Two local deformation modes of porous ductile (single crystals) materials have been…

Perovskite minerals form an essential component of the Earth's mantle, and synthetic crystals are ubiquitous in electronics, photonics, and energy technology. The extraordinary chemical diversity of these crystals raises the question on how…

Reducing the dimensionality of metal-halide perovskites enhances quantum and dielectric confinement, enabling tunable excitonic properties. In one dimension, the arrangement of metal-halide octahedra in chains with corner-, edge-, or…

Under external stimuli, lead halide perovskites exhibit large atomic fluctuations, impacting optical and electron transport properties that affect device performance in operational settings. However, a thorough understanding of the atomic…

We consider resurgence for the nonconformal Bjorken flow with Fermi-Dirac and Bose-Einstein statistics on the extended relaxation-time approximation. We firstly consider full formal transseries expanded around the equilibrium and then…

A supersolid is a counter-intuitive phase of matter where its constituent particles are arranged into a crystalline structure, yet they are free to flow without friction. This requires the particles to share a global macroscopic phase while…

The NaNO$_{2}$ nanocomposite ferroelectric material in porous glass was studied by neutron diffraction. For the first time the details of the crystal structure including positions and anisotropic thermal parameters were determined for the…

Halide perovskites have emerged as one of the most interesting materials for optoelectronic applications due to their favorable properties, such as defect-tolerance and long charge carrier lifetimes, which are attributed to their dynamic…

We use first-principles density functional theory calculations to investigate the dielectric response of BaZrO$_3$ perovskite. A previous study [Arkbarzadeh {\em et al.} Phys. Rev. B {\bf 72}, 205104 (2005)] reported a disagreement between…

The crystal structure of Pb$_{10}$(PO$_4$)$_6$O, the proposed matrix for the potential room-temperature superconductor LK-99, Pb$_{10-x}$Cu$_x$(PO$_4$)$_6$O ($x = 0.9-1.0$), has been reinvestigated by single-crystal X-ray diffraction using…

Superconductivity owes its properties to the phase of the electron pair condensate that breaks the $U(1)$ symmetry. In the most traditional ground state, the phase is uniform and rigid. The normal state can be unstable towards special…

We study the antiferrodistortive instability and its interaction with ferroelectricity in cubic perovskite compounds. Our first-principles calculations show that coexistence of both instabilities is very common. We develop a…

Ferroelectricity in perovskites is known to be suppressed by a moderate hydrostatic pressure. The notion that a polar instability should reappear in a higher pressure regime is well accepted theoretically but experiments have failed so far…

We report the emergence of a transverse dielectric response in PbTiO$_{3}$/SrTiO$_{3}$ superlattices hosting polar vortex structures. Using second-principles simulations, we find that an electric field applied along one direction induces…

The oxygen octahedral tilted domains in 0.90(Bi1/2Na1/2)TiO3-0.5(Bi1/2K1/2)TiO3-0.5BaTiO3 lead-free perovskite piezoelectric ceramic have been studied by transmission electron microscopy (TEM). Selected-area electron diffraction patterns…

In this paper, we propose a general mechanism for the existence of quasicrystals in spatially extended systems (partial differential equations with Euclidean symmetry). We argue that the existence of quasicrystals with higher order…

We predict that a family of antiperovskite materials realize a higher order topological insulator phase, characterized by a previously introduced $\mathbb{Z}_4$ index. A tight binding model and a $k\cdot p$ model are used to capture the…

Ordered oxygen vacancies (OOVs) in perovskites can exhibit long-range order and may be used to direct materials properties through modifications in electronic structures and broken symmetries. Based on the various vacancy patterns observed…