The electron-phonon interaction is well known to create major resistance electron transport in metals and semiconductors, whereas fewer studies are directed its effect on phonon transport, especially semiconductors. We calculate the lifetimes due scattering with electrons (or holes), combine them intrinsic anharmonic phonon-phonon interaction, all from first principles, evaluate of lattice thermal conductivity silicon. Unexpectedly, we find a significant reduction at room temperature as...

We show that thermal rectification (TR) in asymmetric graphene nanoribbons (GNRs) is originated from phonon confinement the lateral dimension, which a fundamentally new mechanism different macroscopic heterojunctions. Our molecular dynamics simulations reveal that, though TR significant nanosized GNRs, it diminishes at larger width. By solving heat diffusion equation, we prove indeed absent both total transfer rate and local flux for bulk-size single materials, regardless of device geometry...

The monolayer of black phosphorus, or ``phosphorene,'' has recently emerged as a two-dimensional semiconductor with intriguing highly anisotropic transport properties. Existing calculations its intrinsic phonon-limited electronic properties so far rely on the deformation potential approximation, which is in general not directly applicable to materials since along one specific direction can scatter electrons traveling all directions. We perform first-principles calculation electron-phonon...

We perform molecular dynamics (MD) simulations with phonon spectral analysis aiming at understanding the two dimensional (2D) thermal transport in suspended and supported graphene. Within framework of equilibrium MD simulations, we energy density (SED) to obtain lifetime individual modes. The per-mode contribution conductivity is then calculated lattice temperature range 300-650 K. In contrast prior studies, our results suggest that from out-of-plane acoustic (or ZA) branch around 25-30%...

The mean-free-paths (MFPs) of energy carriers are critical importance to the nanoengineering better thermoelectric materials.Despite significant progress in first-principlesbased understanding spectral distribution phonon MFPs recent years, electron remains unclear.In this work, we compute dependent scatterings and silicon from first-principles.The electrical conductivity accumulation with respect is compared that thermal illustrate quantitative impact nanostructuring on transport.By...

Two-body interatomic potentials in the Morse potential form have been developed for bismuth telluride, and are used molecular dynamics simulations to predict thermal conductivity. The density-functional theory with local-density approximations is first calculate total energies many artificially distorted ${\text{Bi}}_{2}{\text{Te}}_{3}$ configurations produce energy surface. Then by fitting this surface other experimental data, parameterized. fitted empirical shown reproduce elastic phonon...

Equilibrium molecular dynamics simulations show that graphene nanoribbons (GNRs) with zigzag edges have higher thermal conductivity (κ) than armchair-edged ones, and the difference diminishes increasing temperature or ribbon width. The dominant phonon wavelength for transport can be much longer (by orders of magnitude) between “roughness” smooth armchair edges. Therefore, roughness scattering theory is not sufficient to explain largely different κ GNRs edge chiralities. Cross-sectional...

Significance It has been well known that the phonon drag effect—an extra electrical current induced by heat flow via electron–phonon interaction—can lead to unusually high Seebeck coefficient at low temperatures. However, its use for improving thermoelectric performance controversial. Here, using first principles calculations we examine with detailed mode-specific contributions and reveal even in heavily doped silicon room temperature, can still be significant, which challenges previous...

In this work, we explore the thermal properties of hexagonal transition metal dichalcogenide compounds with different average atomic masses but equivalent microstructures. Thermal conductivity values sputtered thin films were compared to bulk crystals. The comparison revealed a >10 fold reduction in film conductivity. Structural analysis turbostratic structure domain sizes on order 5–10 nm. Estimates phonon scattering lengths at boundaries based computationally derived group...

It is well known that phonon frequencies can shift from their harmonic values when elevated to a finite temperature due the anharmonicity of interatomic potential. Here, we show eigenvectors also have shifts, but only for compound materials in which each atom has at least two types anharmonic interactions with other atoms. Using PbTe as model material, shifts some modes may reach much 50% 800 K. Phonon are used normal mode analysis (NMA) predict relaxation times and thermal conductivity. We...

External light irradiation is usually required in bacterial infection theranostics; however, it always accompanied by limited penetration, imaging interference, and incomplete destruction. Herein, a feasible "image-launching therapy" strategy developed to integrate real-time optical simultaneous photodynamic therapy (PDT) of infections into persistent luminescence (PL) nanoparticles (NPs). Mesoporous silica NPs are used as substrate for situ deposition PL nanodots ZnGa2 O4 :Cr3+ obtain mPL...

Using molecular dynamics simulations, we have predicted the thermal conductivity of Bi${}_{2}$Te${}_{3}$ nanowires with diameters ranging from 3 to 30 nm both smooth and rough surfaces. It is found that when nanowire diameter decreases scale (below 10 nm, or so-called ``quantum wire''), shows significant reduction as compared bulk value. On other hand, for 30-nm-diam only less than 20% reduction, in agreement recent experimental data. Also, a weaker temperature dependence typical...

In this work, we use molecular dynamics simulations to predict the thermal conductivities of perfect and nanoporous few-quintuple Bi2Te3 thin films. We find dimensional crossover behavior transport a minimum conductivity at three quintuple layers room temperature, attribute it interplay between phonon Umklapp scattering boundary scattering. Also, films show significantly reduced compared films, indicating that they can be very promising thermoelectric materials.

Coherent phonon heat conduction has recently been confirmed experimentally in superlattice structures. Such traveling coherent waves superlattices lead to a linear increase thermal conductivity as the number of periods increases. For applications such insulation or thermoelectrics, minimization effect is desirable. In this work, we use molecular dynamics simulations study how control (SLs). It found that either aperiodic SLs with rough interfaces can significantly disrupt when interface...

Helicobacter pylori (H. pylori) is recognized as a pathogenic factor related to gastrointestinal diseases and gastric cancer. The theranostics of H. infection confronted with challenges from colonization on the epithelial cell layer formation bacterial biofilms, which prevent interactions imaging probes antimicrobial agents. Herein, theranostic nanoparticles (NPs) are developed ultrasonication (US)-propelled motion US-excited persistent luminescence for precise efficient eradication pylori....

Thermal properties and transport control are important for many applications, example, low thermal conductivity is desirable thermoelectrics. Knowledge of mode-wise phonon crucial to identify dominant modes design effective barriers control. In this paper, we adopt time-domain (TD) frequency-domain (FD) normal-mode analyses investigate calculate dispersion relations relaxation times in bismuth telluride. Our simulation results agree with the previously reported data obtained from ultrafast...