Browse
Submit Data
Databases
API
Help

Dataset Information

15 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Phonon Engineering in Twinning Superlattice Nanowires.

ABSTRACT: One of the current challenges in nanoscience is tailoring the phononic properties of a material. This has long been a rather elusive task because several phonons have wavelengths in the nanometer range. Thus, high quality nanostructuring at that length-scale, unavailable until recently, is necessary for engineering the phonon spectrum. Here we report on the continuous tuning of the phononic properties of a twinning superlattice GaP nanowire by controlling its periodicity. Our experimental results, based on Raman spectroscopy and rationalized by means of ab initio theoretical calculations, give insight into the relation between local crystal structure, overall lattice symmetry, and vibrational properties, demonstrating how material engineering at the nanoscale can be successfully employed in the rational design of the phonon spectrum of a material.

SUBMITTER: De Luca M

PROVIDER: S-EPMC6628185 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Phonon Engineering in Twinning Superlattice Nanowires.

De Luca Marta M Fasolato Claudia C Verheijen Marcel A MA Ren Yizhen Y Swinkels Milo Y MY Kölling Sebastian S Bakkers Erik P A M EPAM Rurali Riccardo R Cartoixà Xavier X Zardo Ilaria I

Nano letters 20190620 7

One of the current challenges in nanoscience is tailoring the phononic properties of a material. This has long been a rather elusive task because several phonons have wavelengths in the nanometer range. Thus, high quality nanostructuring at that length-scale, unavailable until recently, is necessary for engineering the phonon spectrum. Here we report on the continuous tuning of the phononic properties of a twinning superlattice GaP nanowire by controlling its periodicity. Our experimental result ...[more]

PMID: 31203630

Similar Datasets

GaAs/GaP Superlattice Nanowires for Tailoring Phononic Properties at the Nanoscale: Implications for Thermal Engineering.

Project description:The possibility to tune the functional properties of nanomaterials is key to their technological applications. Superlattices, i.e., periodic repetitions of two or more materials in one or more dimensions, are being explored for their potential as materials with tailor-made properties. Meanwhile, nanowires offer a myriad of possibilities to engineer systems at the nanoscale, as well as to combine materials that cannot be put together in conventional heterostructures due to the lattice mismatch. In this work, we investigate GaAs/GaP superlattices embedded in GaP nanowires and demonstrate the tunability of their phononic and optoelectronic properties by inelastic light scattering experiments corroborated by ab initio calculations. We observe clear modifications in the dispersion relation for both acoustic and optical phonons in the superlattices nanowires. We find that by controlling the superlattice periodicity, we can achieve tunability of the phonon frequencies. We also performed wavelength-dependent Raman microscopy on GaAs/GaP superlattice nanowires, and our results indicate a reduction in the electronic bandgap in the superlattice compared to the bulk counterpart. All of our experimental results are rationalized with the help of ab initio density functional perturbation theory (DFPT) calculations. This work sheds fresh insights into how material engineering at the nanoscale can tailor phonon dispersion and open pathways for thermal engineering.

| S-EPMC10580287 | biostudies-literature

GaAs/GaP superlattice nanowires: growth, vibrational and optical properties.

Project description:Nanowire geometry allows semiconductor heterostructures to be obtained that are not achievable in planar systems, as in, for example, axial superlattices made of large lattice mismatched materials. This provides a great opportunity to explore new optical transitions and vibrational properties resulting from the superstructure. Moreover, superlattice nanowires are expected to show improved thermoelectric properties, owing to the dominant role of surfaces and interfaces that can scatter phonons more effectively, reducing the lattice thermal conductivity. Here, we show the growth of long (up to 100 repetitions) GaAs/GaP superlattice nanowires with different periodicities, uniform layer thicknesses, and sharp interfaces, realized by means of Au-assisted chemical beam epitaxy. By optimizing the growth conditions, we obtained great control of the nanowire diameter, growth rate, and superlattice periodicity, offering a valuable degree of freedom for engineering photonic and phononic properties at the nanoscale. As a proof of concept, we analyzed a single type of superlattice nanowire with a well-defined periodicity and we observed room temperature optical emission and new phonon modes. Our results prove that high-quality GaAs/GaP superlattice nanowires have great potential for phononic and optoelectronic studies and applications.

| S-EPMC9851173 | biostudies-literature

Superlattice valley engineering for designer topological insulators.

Project description:A topological insulator is a novel state of quantum matter, characterized by symmetry-protected Dirac interfacial states within its bulk gap. Tremendous effort has been invested into the search for topological insulators. To date, the discovery of topological insulators has been largely limited to natural crystalline solids. Therefore, it is highly desirable to tailor-make various topological states of matter by design, starting with but a few accessible materials or elements. Here, we establish that valley-dependent dimerization of Dirac surface states can be exploited to induce topological quantum phase transitions, in a binary superlattice bearing symmetry-unrelated interfacial Dirac states. This mechanism leads to a rich phase diagram and allows for rational design of strong topological insulators, weak topological insulators, and topological crystalline insulators. Our ab initio simulations further demonstrate this mechanism in [111] and [110] superlattices of calcium and tin tellurides. While our results reveal a remarkable phase diagram for the binary superlattice, the mechanism is a general route to design various topological states.

| S-EPMC4179471 | biostudies-literature

Three-dimensional superlattice engineering with block copolymer epitaxy.

Project description:Three-dimensional (3D) structures at the nanometer length scale play a crucial role in modern devices, but their fabrication using traditional top-down approaches is complex and expensive. Analogous to atomic lattices, block copolymers (BCPs) spontaneously form a rich variety of 3D nanostructures and have the potential to substantially simplify 3D nanofabrication. Here, we show that the 3D superlattice formed by BCP micelles can be controlled by lithographically defined 2D templates matching a crystallographic plane in the 3D superlattice. Using scanning transmission electron microscopy tomography, we demonstrate precise control over the lattice symmetry and orientation. Excellent ordering and substrate registration can be achieved, propagating through 284-nanometer-thick films. BCP epitaxy also showed exceptional lattice tunability, with a continuous Bain transformation from a body-centered cubic to a face-centered cubic lattice. Lattice stability was mediated by molecular packing frustration, and surface-induced lattice reconstruction was observed, leading to the formation of a unique honeycomb lattice.

| S-EPMC7292617 | biostudies-literature

Pressure-enabled phonon engineering in metals.

Project description:We present a combined first-principles and experimental study of the electrical resistivity in aluminum and copper samples under pressures up to 2 GPa. The calculations are based on first-principles density functional perturbation theory, whereas the experimental setup uses a solid media piston-cylinder apparatus at room temperature. We find that upon pressurizing each metal, the phonon spectra are blue-shifted and the net electron-phonon interaction is suppressed relative to the unstrained crystal. This reduction in electron-phonon scattering results in a decrease in the electrical resistivity under pressure, which is more pronounced for aluminum than for copper. We show that density functional perturbation theory can be used to accurately predict the pressure response of the electrical resistivity in these metals. This work demonstrates how the phonon spectra in metals can be engineered through pressure to achieve more attractive electrical properties.

| S-EPMC4066520 | biostudies-literature

Shape-controlled synthesis of palladium and copper superlattice nanowires for high-stability hydrogen sensors.

Project description:For hydrogen sensors built with pure Pd nanowires, the instabilities causing baseline drifting and temperature-driven sensing behavior are limiting factors when working within a wide temperature range. To enhance the material stability, we have developed superlattice-structured palladium and copper nanowires (PdCu NWs) with random-gapped, screw-threaded, and spiral shapes achieved by wet-chemical approaches. The microstructure of the PdCu NWs reveals novel superlattices composed of lattice groups structured by four-atomic layers of alternating Pd and Cu. Sensors built with these modified NWs show significantly reduced baseline drifting and lower critical temperature (259.4 K and 261 K depending on the PdCu structure) for the reverse sensing behavior than those with pure Pd NWs (287 K). Moreover, the response and recovery times of the PdCu NWs sensor were of ~9 and ~7 times faster than for Pd NWs sensors, respectively.

| S-EPMC3895925 | biostudies-literature

Artificial visual systems enabled by quasi-two-dimensional electron gases in oxide superlattice nanowires.

Project description:Rapid development of artificial intelligence techniques ignites the emerging demand on accurate perception and understanding of optical signals from external environments via brain-like visual systems. Here, enabled by quasi-two-dimensional electron gases (quasi-2DEGs) in InGaO3(ZnO)3 superlattice nanowires (NWs), an artificial visual system was built to mimic the human ones. This system is based on an unreported device concept combining coexistence of oxygen adsorption-desorption kinetics on NW surface and strong carrier quantum-confinement effects in superlattice core, to resemble the biological Ca2+ ion flux and neurotransmitter release dynamics. Given outstanding mobility and sensitivity of superlattice NWs, an ultralow energy consumption down to subfemtojoule per synaptic event is realized in quasi-2DEG synapses, which rivals that of biological synapses and now available synapse-inspired electronics. A flexible quasi-2DEG artificial visual system is demonstrated to simultaneously perform high-performance light detection, brain-like information processing, nonvolatile charge retention, in situ multibit-level memory, orientation selectivity, and image memorizing.

| S-EPMC7673733 | biostudies-literature

Self-heating hotspots in superconducting nanowires cooled by phonon black-body radiation.

Project description:Controlling thermal transport is important for a range of devices and technologies, from phase change memories to next-generation electronics. This is especially true in nano-scale devices where thermal transport is altered by the influence of surfaces and changes in dimensionality. In superconducting nanowire single-photon detectors, the thermal boundary conductance between the nanowire and the substrate it is fabricated on influences all of the performance metrics that make these detectors attractive for applications. This includes the maximum count rate, latency, jitter, and quantum efficiency. Despite its importance, the study of thermal boundary conductance in superconducting nanowire devices has not been done systematically, primarily due to the lack of a straightforward characterization method. Here, we show that simple electrical measurements can be used to estimate the thermal boundary conductance between nanowires and substrates and that these measurements agree with acoustic mismatch theory across a variety of substrates. Numerical simulations allow us to refine our understanding, however, open questions remain. This work should enable thermal engineering in superconducting nanowire electronics and cryogenic detectors for improved device performance.

| S-EPMC9481646 | biostudies-literature

Carrier-phonon decoupling in perovskite thermoelectrics via entropy engineering.

Project description:Thermoelectrics converting heat and electricity directly attract broad attentions. To enhance the thermoelectric figure of merit, zT, one of the key points is to decouple the carrier-phonon transport. Here, we propose an entropy engineering strategy to realize the carrier-phonon decoupling in the typical SrTiO3-based perovskite thermoelectrics. By high-entropy design, the lattice thermal conductivity could be reduced nearly to the amorphous limit, 1.25 W m-1 K-1. Simultaneously, entropy engineering can tune the Ti displacement, improving the weighted mobility to 65 cm2 V-1 s-1. Such carrier-phonon decoupling behaviors enable the greatly enhanced μW/κL of ~5.2 × 103 cm3 K J-1 V-1. The measured maximum zT of 0.24 at 488 K and the estimated zT of ~0.8 at 1173 K in (Sr0.2Ba0.2Ca0.2Pb0.2La0.2)TiO3 film are among the best of n-type thermoelectric oxides. These results reveal that the entropy engineering may be a promising strategy to decouple the carrier-phonon transport and achieve higher zT in thermoelectrics.

| S-EPMC11369264 | biostudies-literature

Impact of Phonon Surface Scattering on Thermal Energy Distribution of Si and SiGe Nanowires.

Project description:Thermal transport in nanostructures has attracted considerable attention in the last decade but the precise effects of surfaces on heat conduction have remained unclear due to a limited accuracy in the treatment of phonon surface scattering phenomena. Here, we investigate the impact of phonon-surface scattering on the distribution of thermal energy across phonon wavelengths and mean free paths in Si and SiGe nanowires. We present a rigorous and accurate description of phonon scattering at surfaces and predict and analyse nanowire heat spectra for different diameters and surface conditions. We show that the decrease in the diameter and increased roughness and correlation lengths makes the heat phonon spectra significantly shift towards short wavelengths and mean free paths. We also investigate the emergence of phonon confinement effects for small diameter nanowires and different surface scattering properties. Computed results for bulk materials show excellent agreement with recent experimentally-based approaches that reconstruct the mean-free-path heat spectra. Our phonon surface scattering model allows for an accurate theoretical extraction of heat spectra in nanowires and contributes to elucidate the development of critical phonon transport modes such as phonon confinement and coherent interference effects.

| S-EPMC4865844 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data