On the possibility of observing electron-phonon UMKLAPP-processes in photoconductive spectral response of semiconductorsDips in the photoconductive spectral response of many-valleyed semiconductors at multiples of the intervalley phonon emission threshold energies are predicted; in analogy to the ...
In this work, by adopting a set of realasymmetric normal mode amplitudes, we first discriminate the normal and Umklapp processes directly from atomistic dynamics. We then demonstrate that the undulating harmonic and anharmonic potentials, which allow a number of interaction pathways, generate several ...
complicated scattering processes of InSe. Importantly, similar deviations have been observed in several thermoelectric materials and are attributed to highly anharmonic rattling dynamics26. This resonates with the idea that strongly damped dynamical modes can induce glass-like properties without necessarily ...
Above this temperature, the decrease in κ is due to phonon–phonon scattering involving umklapp processes [146]. It is interesting to compare this bulk data to that of nanowires and to diamond which is isostructural to Si. Diamond is the best (lattice) thermal conductor known and has the ...
leading to a dramatical increase in the phonon relaxation rates in defects and Umklapp processes [68]. The reduction of thermal conductivity is beneficial to the improvement of the performance of thermoelectric devices, but it makes thermal management of microelectronic devices a challenge. Later, sch...
(Umklapp) scattering processes at low temperatures. This results in well-defined bands, such that phonon tunneling is diminished. In contrast, the massive reduction of phonon lifetimes at 400 K reduces particle-like transport and\({\kappa }_{P}^{{av}}\)below 5 THz accounts for only ...
其中R过程通常又包括: 三声子U过程(Umklapp Process)、声子-缺陷散射和声子-边界散射. 声子散射过程的粒子数通常不守恒, 但能量总是守恒的. R过程损失了部分声子准动量, 是晶体热阻的直接产生来源, 而N过程则通过改变声子的频谱分布间接产生热阻. 原始声子碰撞项十分复杂, 使得声子Boltzmann方程的求解十分困难. 与...
the estimated order of the decay, known as the 'frequency-gap law'17, has shown that one-phonon processes (resonant coupling) occur within a few tenths of a ps, while two- and three-phonon processes involve 5–10 ps and over 80 ps, respectively. Similar times scales are eTx0piA...
The recent achievement of ab initio calculations of the thermal conductivity of a type-I clathrate, based on intrinsic phonon-phonon Umklapp scattering processes23, represents a major step forward. It showed that, unlike in the resonance scattering picture, the phonon lifetimes are reduced in a ...
4) Umklapp process 反转过程,倒逆过程;碰撞过程;U过程(声子的一种相互碰撞过程)5) quantum teleflipping 量子远程翻转6) three-photon process 三光子过程补充资料:多声子过程(见非简谐效应) 多声子过程(见非简谐效应) multiphonon process 多声子过程multiphonon proeess见非简谐效应。 说明:补充资料仅用于...