Related papers: Static and Dynamic Disorder in Formamidinium Lead …
A thorough understanding of the temperature dependence of semiconductor band gaps is essential for optimizing optoelectronic devices. In this respect, the origin of the pronounced temperature-induced gap bowing observed in low-temperature…
We have performed for the first time micro-Raman studies of lysozyme crystals for the temperatures lower than the room one (in the range 282-300K). Anomalous temperature dependence of the positions of Raman scattering bands has been…
The stability of the four known stationary points of the cubic helimagnet energy functional: the ferromagnetic state, the conical helix, the conical helicoid, and the skyrmion lattice, is studied by solving the corresponding spectral…
Lithium doped sodium niobate is an ecofriendly piezoelectric material that exhibits a variety of structural phase transitions with composition and temperature. We have investigated the phase stabilities of an important composition…
$\delta$-Bi$_2$O$_3$ is one of the fastest known solid oxide ion conductors owing to its intrinsically defective fluorite-like structure with 25\% vacant sites in the O sub-lattice. Numerous diffraction measurements and molecular dynamics…
We present a revised atomistic picture of the order-disorder transition in the archetypal orbital-ordered perovskite material, LaMnO$_{3}$. Our study uses machine-learning-driven molecular-dynamics simulations which describe the temperature…
Mixing iodide and bromide in halide perovskite semiconductors is an effective strategy to tune their bandgap, therefore mixed-halide perovskites hold great promise for color-tunable LEDs and tandem solar cells. However, the bandgap of…
The family of organic-inorganic tri-halide perovskites including MA (MethylAmmonium)PbI$_{3}$, MAPbI$_{3-x}$Cl$_{x}$, FA (FormAmidinium)PbI$_{3}$ and FAPbBr$_{3}$ are having a tremendous impact on the field of photovoltaic cells due to…
Halide pervoskites are an important class of semiconducting materials which hold great promise for optoelectronic applications. In this work we investigate the relationship between vibrational anharmonicity and dynamic disorder in this…
Recently, halide perovskites have gained significant attention from the perspective of efficient spintronics owing to Rashba effect. This effect occurs as a consequence of strong spin-orbit coupling under noncentrosymmetric environment,…
The high-pressure crystal structure evolution of CH3NH3PbBr3 (MAPbBr3) perovskite has been investigated by single-crystal X-ray diffraction and synchrotron-based powder X-ray diffraction. Single-crystal X-ray diffraction reveals that the…
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…
Methylammonium-lead-halide compounds have emerged as promising bandgap engineering materials due to their ability to fine-tune the energy gap through halogen element mixing. We present a comprehensive investigation of the…
The lattice properties at low temperatures of two samples of NdFeAsO1-xFx (x=0.05 and 0.25) have been examined in order to investigate possible structural phase transition that may occur in the optimally doped superconducting sample with…
The optoelectronic properties and ultimately photovoltaic performance of hybrid lead halide perovskites, is inherently related to the dynamics of the organic cations. Here we report on the dynamics of the formamidinium (FA) cation in FAPbX3…
The structure and the dielectric properties of Pb(Zn1/3Nb2/3)O3 (PZN) crystal have been investigated by means of high-resolution synchrotron x-ray diffraction (with an x-ray energy of 32 keV) and dielectric spectroscopy (in the frequency…
Lead-halide perovskites are promising materials for opto-electronic applications. Recent reports indicated that their mechanical and electronic properties are strongly affected by the lattice vibrations. Herein we report far-infrared…
We study the statics and the dynamics of domain patterns in proper hexagonal-orthorhombic ferroelastics; these patterns are of particular interest because they provide a rare physical realization of disclinations in crystals. Both our…
Halide perovskite materials have been extensively studied in the last decade because of their impressive optoelectronic properties. However, their one characteristic that is uncommon for semiconductors is that many undergo thermally induced…
Lattice dynamics for five ordered PMN supercells were calculated from first principles by the frozen phonon method. Maximal symmetries of all supercells are reduced by structural instabilities. Lattice modes corresponding to these…