The Faddeev technique is employed to address the problem of describing the influence of both particleparticle and particle-hole phonons on the single-particle self-energy. The scope of the few-body Faddeev equations is extended to describe the motion of two-hole–one-particle ~two-particle–one-hole! excitations. This formalism allows one to sum both particle-particle and particle-hole phonons, o...

Thermal conductivity measurements over variable lengths on nanostructures such as nanowires provide important information about the mean free paths (MFPs) of the phonons responsible for heat conduction. However, nearly all of these measurements have been interpreted using an average MFP even though phonons in many crystals possess a broad MFP spectrum. Here, we present a reconstruction method t...

We examine the intrinsic energy dissipation steps in electrically biased graphene channels. By combining in-situ measurements of the spontaneous optical emission with a Raman spectroscopy study of the graphene sample under conditions of current flow, we obtain independent information on the energy distribution of the electrons and phonons. The electrons and holes contributing to light emission ...

Brillouin spectroscopy has been used to characterize shear acoustic phonons in materials. However, conventional instruments had slow acquisition times over 10 min per 1 mW of input optical power, and they required two objective lenses to form a 90° scattering geometry necessary for polarization coupling by shear phonons. Here, we demonstrate a confocal Brillouin microscope capable of detecting ...

The accuracy of predictions of the thermal boundary conductance (hBD) made using traditional models such as the diffuse mismatch model (DMM) varies depending on the types of material comprising the interface. At interfaces of materials with very different material properties, the discrepancy between the measured hBD and the DMM results has been associated with inelastic scattering. In this stud...

Pseudogaps due to sound modes: from incommensurate charge density waves to semiconducting wires. Abstract We consider pseudogap effects for electrons interacting with gapless modes. We study both generic 1D semiconductors with acoustic phonons and incom-mensurate charge density waves. We calculate the subgap absorption as it can be observed by means of the photo electron or tunneling spectrosco...

We explore the feasibility of reducing the lifetime of longitudinal optical phonons in InP by injecting coherent longitudinal acoustic modes of frequency given by the difference between those of the longitudinal and transverse optical phonons. Calculations show that a ten-fold reduction in the lifetime can be attained using a 40 mW acoustic source. The increase in the phonon decay should reduce...

9.1 Harmonic Oscillator 9.1.1 Classical harmonic oscillator and h.o. model 9.1.2 Oscillator Hamiltonian: Position and momentum operators 9.1.3 Position representation 9.1.4 Heisenberg picture 9.1.5 Schrödinger picture 9.2 Uncertainty relationships 9.3 Coherent States 9.3.1 Expansion in terms of number states 9.3.2 Non-Orthogonality 9.3.3 Uncertainty relationships 9.3.4 X-representation 9.4 Phon...

We present a systematic analysis of ground state properties of a tunneling system coupled to an Ohmic bath. The nonadiabatic effects induced by coupling with tunneling particle , on the ground state properties of phonons are taken into account. For this we have considered both displacement and deformation of phonons via a variational treatment. The symmetry breaking transition , or the delocali...

In this presentation, we report the calculated results on hot electron relaxation through interand intra-subband scatterings with LO phonons in quantum well structures. The scattering rates were calculated for electrons excited both in the gamma valley and L valleys. The types of optical phonons adapted in our model are determined based on the dielectric continuum model. We have also studied th...