The low-frequency vibrational and low-temperature thermal properties of amorphous solids are markedly different from those crystalline solids. This situation is counter-intuitive because any solid material expected to behave as a homogeneous elastic body in the continuum limit, which modes phonons following Debye law. A number phenomenological explanations have been proposed, assume heterogeneities, soft localized vibrations, so on. Recently, microscopic mean-field theories developed predict...

Glasses exhibit spatially inhomogeneous elastic properties, which can be investigated by measuring their moduli at a local scale. Various methods to evaluate the modulus have been proposed in literature. A first possibility is measure stress-local strain curve and obtain from slope of curve, or equivalently use fluctuation formula. Another possible route assume an affine applied global instead for calculation modulus. Most recently third technique has introduced, easy implemented advantage...

Significance What makes the difference when sound propagation is investigated in a crystal or glass? One hundred years ago, Debye rationalized former case terms of phonons. In contrast, effort have failed to provide convincing picture for vibrations disordered solids. We contribution this issue by reporting clear evidence that mechanical feature, elastic heterogeneity at nanoscale, profoundly affects main properties and even very nature waves. Our picklock numerical study toy model that,...

The low-temperature properties of amorphous solids are widely believed to be controlled by the low-frequency quasilocalized modes. However, what governs their spatial structure and density is unclear. We study these questions numerically in very large systems as jamming transition approached pressure $p$ vanishes. find that modes consist an unstable core a stable far-field component. length scale diverges ${p}^{\ensuremath{-}1/4}$ its characteristic volume ${p}^{\ensuremath{-}1/2}$. These...

One of the long-standing issues concerning thermal properties amorphous solids is complex pattern phonon transport. Recent advances in experiments and computer simulations have indicated a crossover from Rayleigh scattering to viscous damping. A number theories been proposed, yet critical tests are missing validity these unclear. In particular, precise location frequency remains controversial, more critically, even itself has seriously questioned. The present work settles by using...

The low-temperature thermal properties of glasses are anomalous with respect to those crystals. These anomalies indicate that the low-frequency vibrational differ from Recent studies revealed that, in simplest model glasses, i.e., harmonic potential system, phonon modes coexist soft localized (continuum) limit. However, nature more realistic models is still controversial. In present work, we study Lennard-Jones (LJ) system using large-scale molecular-dynamics (MD) simulation and establish...

Abstract The value measured in the amorphous structure with same chemical composition is often considered as a lower bound for thermal conductivity of any material: heat carriers are strongly scattered by disorder and their lifetimes reach minimum time scale vibrations. An appropriate design at nano-scale, however, may allow one to reduce even below limit. In present contribution, using molecular-dynamics simulation Green-Kubo formulation, we study systematically layered phononic materials...

This paper presents the results of an experimental investigation microwave characteristics a GaAs MESFET under optically direct-controlled conditions. The gain, drain current, and S-parameters were measured various optical conditions in frequency region from 3.0 GHz to 8.0 GHz, it was found that they can be controlled by varying incident light intensity same manner as when gate bias voltage. As applications this phenomenon, optical/microwave transformers switched amplifier investigated.

Recent progress on studies of the nanoscale mechanical responses in disordered systems has highlighted a strong degree heterogeneity elastic moduli. In this contribution, using computer simulations, we study heterogeneities athermal amorphous solids, composed isotropic, static, sphere packings, near jamming transition. We employ techniques, based linear response methods, that are amenable to experimentation. find local moduli randomly distributed space and described by Gaussian probability...

Electrokinetic flows of an aqueous NaCl solution in nanochannels with negatively charged surfaces are studied using molecular dynamics simulations. The four transport coefficients that characterize the response to weak electric and pressure fields, namely, for electrical current field (M(jj)) (M(jm)), those mass flow same fields (M(mj) M(mm)), obtained linear regime a Green-Kubo approach. Nonequilibrium simulations explicit external also carried out, directly obtained. two methods exhibit...

When we elastically impose a homogeneous, affine deformation on amorphous solids, they also undergo an inhomogeneous, non-affine deformation, which can have crucial impact the overall elastic response. To correctly understand modulus $M$, it is therefore necessary to take into account not only $M_A$, but $M_N$ that arises from deformation. In present work, study bulk ($M=K$) and shear ($M=G$) moduli in static jammed particulate packings over range of packing fractions $\varphi$. One novelty...

Amorphous packings prepared in the vicinity of jamming transition play a central role theoretical studies vibrational spectrum glasses. Two mean-field theories predict that density states $g(\ensuremath{\omega})$ obeys characteristic power law, $g(\ensuremath{\omega})\ensuremath{\sim}{\ensuremath{\omega}}^{2}$, called non-Debye scaling low-frequency region. Numerical have, however, reported this breaks down at low frequencies, due to finite-dimensional effects. In study, we prepare amorphous...

The low-frequency vibrations of glasses are markedly different from those crystals. These have recently been categorized into two types: spatially extended vibrations, whose vibrational density states (vDOS) follows a non-Debye quadratic law, and quasilocalized (QLVs), vDOS quartic law. former explained by elasticity theory with quenched disorder microscopic replica as being consequence elastic instability, but the origin latter is still debated. Here, we show that can also be directly...

Understanding glass formation by quenching remains a challenge in soft condensed matter physics.

Boson peak (BP) dynamics refers to the universal excitation in terahertz region of glass. In this study, BP were quantitatively evaluated various glassy materials based on heterogeneous elasticity theory (HET), and determinants successfully extracted. A strong correlation was observed between maximum possible coarse-graining wavenumber, which is a determinant HET, first sharp diffraction (FSDP) characteristic index medium-range order glasses. The results indicate that behaviour glass can be...

Abstract Amorphous solids are diverse materials that take on various forms such as structural glasses, granular materials, foams, emulsions, and biological systems. Recent research has made significant progress in understanding non-phonon vibrational modes universally present amorphous which have been observed excess over the Debye law, known boson peak, well quasi-localized modes. These crucial to explaining material properties of a wide range from “hard" like glasses “soft" foams...

Granular materials are defined as collections of macroscopic dissipative particles. Although these systems ubiquitous in our lives, the nature and causes their non-trivial collective dynamics still remain elusive have attracted significant interest non-equilibrium physics. Here, we focus on vibrational granular materials. While random packings been examined concerning jamming transition, previous research has overlooked role contact dissipations. We conducted numerical analytical...

Abstract Boson peak (BP) dynamics refers to the universal excitation in terahertz region of glass. In this study, BP were quantitatively evaluated various glassy materials based on heterogeneous elasticity theory (HET), and determinants successfully extracted. A strong correlation was observed between maximum possible coarse-graining wavenumber, which is a determinant HET, first sharp diffraction (FSDP) characteristic index medium-range order glasses. The results indicate that behaviour...

Granular materials are defined as collections of macroscopic dissipative particles. Although these systems ubiquitous in our lives, the nature and causes their non-trivial collective dynamics still remain elusive have attracted significant interest non-equilibrium physics. Here, we focus on vibrational granular materials. While random packings been examined concerning jamming transition, previous research has overlooked role contact dissipations. We conducted numerical analytical...

Disordered solids exhibit unusual properties of their vibrational states and thermal conductivities. Recent progresses have well established the concept "elastic heterogeneity", i.e., disordered materials show spatially inhomogeneous elastic moduli. In this study, by using molecular-dynamics simulations, we gradually introduce "disorder" into a numerical system to control its modulus heterogeneity. The starts from perfect crystalline state, progressively transforms an increasingly finally...

In crystals, molecules thermally vibrate around the periodic lattice sites. Vibrational motions are well understood in terms of phonons, which carry heat and control transport. The situation is notably different disordered solids, where vibrational excitations not phonons can be even localized. Recent numerical work has established concept elastic heterogeneity: solids show inhomogeneous local mechanical response. Clearly, heterogeneous nature properties strongly influences thermal...

The boson peak is a largely unexplained excitation found universally in the terahertz vibrational spectra of disordered systems; so-called fracton associated with self-similar structure monomers polymeric glasses. We demonstrate that such excitations can be detected using spectroscopy. In case fractal structures, we determine infrared light-vibration coupling coefficient for region and show information concerning dimensions appears exponent absorption coefficient. Finally, time-domain...

Plastic events in sheared glasses are considered an example of so-called avalanches, whose sizes obey a power-law probability distribution with the avalanche critical exponent $\ensuremath{\tau}$. Although mean-field depinning (MFD) theory predicts universal value this exponent, ${\ensuremath{\tau}}_{\mathrm{MFD}}=1.5$, such simplification is now known to connote qualitative disagreement realistic systems. Numerically and experimentally, different values $\ensuremath{\tau}$ have been...

Supercooled liquids undergo complicated structural relaxation processes, which have been a long-standing problem in both experimental and theoretical aspects of condensed matter physics. In particular, past experiments widely observed for many types molecular that dynamics separated into two distinct processes at low temperatures. One the possible interpretations is this separation originates from two-scale hierarchical topography potential energy landscape; however, it has never verified....