Oxide-based valence-change memristors are promising nonvolatile memories for future electronics that operate on reactions to modulate their electrical resistance. The memristance is associated with the movement of oxygen ionic carriers through vacancies at high electric field strength via structural defect modifications still poorly understood. This study employs a Ce1–xGdxO2–y solid solution model probe role either set as "free" or "immobile and clustered" resistive switching performance....

Gd-doped CeO(2) exhibits an anomalously large electrostriction effect generating stress that can reach 500 MPa. In situ XANES measurements indicate the develops in response to rearrangement of cerium-oxygen vacancy pairs. This mechanism is fundamentally different from materials currently use and suggests ceria a representative new family high-performance electromechanical materials.

Recent investigations of two-dimensional (2D) hybrid organic-inorganic halide perovskites (HHPs) indicate that their optical and electronic properties are dominated by strong coupling to thermal fluctuations. While the 2D-HHPs have been extensively studied, a comprehensive understanding electron-phonon interactions is limited because little known about structural dynamics. This partially unit cells contain many atoms. Therefore, fluctuations complex difficult elucidate in detail. To overcome...

Lead-based halide perovskite crystals are shown to have strongly anharmonic structural dynamics. This behavior is important because it may be the origin of their exceptional photovoltaic properties. The double perovskite, Cs2 AgBiBr6 , has been recently studied as a lead-free alternative for optoelectronic applications. However, does not exhibit excellent activity lead-based perovskites. Therefore, explore correlation between dynamics and properties in perovskites, investigated compared its...

Studying electric field-induced structural changes in ceramics is challenging due to the very small magnitude of atomic displacements. We used differential X-ray absorption spectroscopy, an elementally specific and spatially sensitive method, detect such Gd-doped ceria, recently shown exhibit giant electrostriction. found that large electrostrictive stress generation can be associated with a few percent unusually short Ce-O chemical bonds change their length degree order under external...

We show that formamidinium-based crystals are distinct from methylammonium-based halide perovskite because their inorganic sublattice exhibits intrinsic local static disorder coexists with a well-defined average crystal structure. Our study combines terahertz-range Raman scattering single-crystal X-ray diffraction and first-principles calculations to probe the evolution of dynamics temperature in range 10-300 K. The spectra shows low-temperature, strongly affects structural phase transitions...

The anharmonic lattice dynamics of oxide and halide perovskites play a crucial role in their mechanical optical properties. Raman spectroscopy is one the key methods used to study these structural dynamics. However, despite decades research, existing interpretations cannot explain temperature dependence observed spectra. We demonstrate nonmonotonic evolution with scattering intensity present model for second-order that accounts this unique trend. By invoking low-frequency feature, we are...

We investigated the local environment of Ce and Gd ions in one most important oxygen ion conductors, CeO${}_{2}$-Gd${}_{2}$O${}_{3}$ solid solution, using ${L}_{\mathrm{III}}$ edge extended x-ray absorption fine structure (EXAFS) spectroscopy near (XANES). The average Gd-O distance, as deduced by EXAFS, decreases gradually with increasing content, whereas a sharp decrease Ce-O distance occurs at 25 mol$%$ Gd, accompanying appearance structural features characteristic double fluorite...

Classical electrostriction, describing a second‐order electromechanical response of insulating solids, scales with elastic compliance, S, and inversely dielectric susceptibility, ε . This behavior, first noted 20 years ago by Robert Newnham, is shown to apply wide range electrostrictors including polymers, glasses, crystalline linear dielectrics, relaxor ferroelectrics. Electrostriction in fluorite ceramics (Y, Nb)‐stabilized δ ‐Bi 2 O 3 examined 16%–23% vacant oxygen sites. Given the values...

Halide perovskite (HP) semiconductors exhibit unique strong coupling between the electronic and structural dynamics. We use Raman polarization-orientation (PO) measurements ab initio molecular dynamics (AIMD) to investigate origin temperature evolution of anharmonicity throughout tetragonal phase $\mathrm{C}{\mathrm{H}}_{3}\mathrm{N}{\mathrm{H}}_{3}\mathrm{Pb}{\mathrm{I}}_{3}$. PO reveal a soft modelike spectral feature. This mode shows an unusual continuous increase in damping with which is...

Basic understanding of the driving forces ion conduction in solids is critical to development new solid-state conductors. Physical limited due strong deviations from harmonic vibrational dynamics these systems that are difficult characterize experimentally and theoretically. We overcome this challenge superionic AgI by combining THz-frequency Raman polarization-orientation measurements ab-initio molecular computations. Our findings demonstrate clear signatures coupling between mobile ions...

Abstract The kinetics of point‐defect association/dissociation reactions in Ce 0.8 Gd 0.2 O 1.9 and their influence on the crystal lattice parameter are investigated by monitoring thermally induced stress strain substrate‐ self‐supported thin films. It is found that, temperature range 100–180 °C, substrate‐supported films lateral dimensions annealed, both exhibit a hysteretic behavior consistent with dissociation/association oxygen vacancy–aliovalent dopant complexes. This leads to strong...

Lone-pair covalency can faciliate dynamic tilting of MBr₆ octahedra and increase structural instabilities.

We combine temperature-dependent low-frequency Raman measurements and first-principles calculations to obtain a mechanistic understanding of the order–disorder phase transition 2,7-di-tert-butylbenzo[b]benzo[4,5]thieno[2,3-d]thiophene (ditBu-BTBT) 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) semiconducting amphidynamic crystals. identify lattice normal modes associated with by following position width peaks temperature identifying that exhibit nonlinear dependence toward...

Abstract Ternary nitride semiconductors are rapidly emerging as a promising class of materials for energy conversion applications, offering an appealing combination strong light absorption in the visible range, desirable charge transport characteristics, and good chemical stability. In this work, it is shown that finite‐temperature lattice dynamics CuTaN 2 – prototypical ternary displaying particularly exhibit pronounced anharmonic character plays essential role defining its macroscopic...

Abstract The influence of dopant size and oxygen vacancy concentration on the room temperature elastic modulus creep rate ceria doped with Pr 4+ , 3+ Lu Gd is investigated using a nanoindentation technique. Measurements are conducted both fast (15 mN s −1 ) slow (0.15 loading modes, including load‐hold stage at 150 8 30 s, respectively. Based data obtained mode, it found that: 1) primary determinant modulus—the larger dopants (Pr produce lower unrelaxed moduli which independent...

Abstract The intermolecular lattice vibrations in small‐molecule organic semiconductors have a strong impact on their functional properties. Existing models treat the within harmonic approximation. In this work, polarization‐orientation (PO) Raman measurements are used to monitor temperature‐evolution of symmetry anthracene and pentacene single crystals. Combined with first‐principles calculations, it is shown that at 10 K, dynamics crystals indeed harmonic. However, as temperature...

In the last decade, hybrid organic-inorganic halide perovskites have emerged as a new type of semiconductor for photovoltaics and other optoelectronic applications. Unlike standard, tetrahedrally bonded semiconductors (e.g., Si GaAs), ionic thermal fluctuations in (i.e., structural dynamics) are strongly coupled to electronic dynamics. Therefore, it is crucial obtain accurate detailed knowledge about nature atomic motions within crystal. This has proved be challenging due low stability...

We combine ab initio simulations and Raman scattering measurements to demonstrate explicit anharmonic effects in the temperature dependent dielectric response of a NaCl single crystal. measure evolution its spectrum compare it both quasi-harmonic model. Results necessity including lattice dynamics explain NaCl, as is manifested scattering. Our model fully captures linear crystal at finite temperatures may therefore be used calculate dependence other material properties governed by it.

One of the major problems in molecular electronics is how to make electronically conducting contact "soft" organic and biomolecules without altering molecules. As a result, only small number metals can be applied, mostly by special deposition methods with severe limitations. Transferring predefined thin metal leaf onto layer provides nondestructive, noninvasive contacting method that is, principle, applicable many types variety metal/molecules combinations. Here we report modification our...

Abstract Using a semiconductor as the substrate to molecular organic layer, penetration of metal contacts can be clearly identified by study electronic charge transport through layer. A series monolayers saturated hydrocarbon molecules with varying lengths is assembled on Si or GaAs and junctions resulting after further contact made liquid Hg, indirect evaporation, “ready‐made” pad are measured. In contrast tunneling characteristics, which ambiguous regarding penetration, surface barrier...