Monte Carlo simulation is applied to investigate phonon transport in single crystalline Si nanowires. Phonon-phonon normal N and Umklapp U scattering processes are modeled with a genetic algorithm to satisfy energy and momentum conservation. The scattering rates of N and U scattering processes are found from first-order perturbation theory. The thermal conductivity of Si nanowires is simulated ...

Using the density-functional theory within the Full Potential Linear Augmented PlaneWave (FP-LAPW) method, we have calculated, in this work, the equation of state, the e ective charges and the phonon dispersion along [100] and [111] directions for the cubic III-Nitrides(c-BN, c-AlN, c-GaN and c-InN), including hydrostatic strains dependence. A good agreement with the micro-Raman scattering expe...

We observe a series of sharp resonant features in the differential conductance of graphene-hexagonal boron nitride-graphene tunnel transistors over a wide range of bias voltages between 10 and 200 mV. We attribute them to electron tunneling assisted by the emission of phonons of well-defined energy. The bias voltages at which they occur are insensitive to the applied gate voltage and hence inde...

We have undertaken an inelastic neutron scattering study of the perovskite relaxor ferroelectric Pb(Zn(1/3)Nb(2/3))O3 with 8% PbTiO3 (PZN-8%PT) in order to elucidate the origin of the previously reported unusual kink on the low frequency transverse phonon dispersion curve (known as the "waterfall effect"). We show that its position (q(wf)) depends on the choice of the Brillouin zone and that th...

The TA2 phonon dispersion curves of Ni-Mn-Ga alloys with different compositions which transform to different martensitic structures have been measured over a broad temperature range covering both paramagnetic and ferromagnetic phases. The branches show an anomaly (dip) at a wave number that depends on the particular martensitic structure, and there is softening of these anomalous phonons with d...

The inelastic scattering of x-rays, one of the the first applications of x-rays to the field of condensed matter physics, has been rejuvenated in the last decade. The availability of synchrotrons radiation from wiggler and undulator sources combined with advances in monochromatization of the incident beam and analysis of the scattered beam with meV resolution led to the measurement of phonon di...

We present a comprehensive analysis of double-resonant Raman scattering in graphite and derive an analytical expression for the Raman cross section of the D mode in one dimension. The extension to two dimensions does not change the double-resonant phonon wave vectors. In the full integration of the Raman cross section, the contributions by phonons from exactly the K point cancel due to destruct...

We present an effective field theory for the crystalline color super-conductivity phase of QCD. It is kown that at high density and at low temperature QCD exhibits a transition to a color superconduct-ing phase characterized by energy gaps in the fermion spectra. Under specific circumstances the gap parameter has a crystalline pattern, breaking translational and rotational invariance. The corre...

We present the concept of a locally resonant nanophononic metamaterial for thermoelectric energy conversion. Our configuration, which is based on a silicon thin film with a periodic array of pillars erected on one or two of the free surfaces, qualitatively alters the base thin-film phonon spectrum due to a hybridization mechanism between the pillar local resonances and the underlying atomic lat...

in this study, bio-based carbon nanotubes (cnts) have received considerable research attention due to their comparative advantages of high level stability, simplistic use, low toxicity and overall environmental friendliness. new potentials for improvement in heat transfer applications are presented due to their high aspect ratio, high thermal conductivity and special surface area. phonons have ...