Electronphonon interaction and transport properties of. Today it is possible to calculate from first principles many materials properties related to the. Electron phonon interaction in a semiconductor is the main factor for relaxation of a transferred electron. Electronphonon coupling can be derived from the deviation of electronic energy by lattice deformation temperature dependence of resistivity at high temperature at low temperature. The possible way to calculate the nonpolar electronphonon matrix elements using dft is discussed and the rigidion approximation is developed in detail. It is a model that describes the lowenergy physics of an electronic system whose behaviour is welldescribed in the limit of the vanishing electron. As an electron moves past atoms in the lattice its charge distorts or polarizes the nearby lattice. Pdf the electronphonon interaction in metals researchgate. Electronphonon coupling in singlelayer mos2 sciencedirect. Available formats pdf please select a format to send. The electronphonon interaction is expanded in powers of the in teraction which involv es the singleion potential of the electrons in the potential of the ions.
They can be viewed as bosonic parti cles which propagate through the crystal and interact with electrons. The electronphonon ep interaction and the empirical pseudopotential method for the discussion of the electronphonon interaction it is strictly necessary to count with a satisfactory description of the electronic states as well as the spectrum of vibrations of the solid. In second order, there is an effective interaction between the quasiparticle excitations of the normal state which is. The electronphonon interaction in metals goran grimvall. In general, equation 1 is capable of modeling a nelectron system. The last me chanism combined with the elastic electron scattering and. Electronphonon interaction an overview sciencedirect. The theory of raman scattering by the electronphonon coupled system in metals and heavily doped semiconductors is developed taking into account the coulomb. When split in this way, the interaction term represents the interactions of the. There are two different relaxation processes that decrease the efficiency of light conversion in a solar system. They are also at the origin of such phenomena as superconductivity. But electronlattice interactions do much more than just cause resistance. This effect leads to a decrease in the electron or hole, as may be the case mobility, which results in a decreased conductivity. Electronphonon interaction and transport properties of metallic bulk and monolayer transition metal dichalcogenide tas2.
Moreover, we studied electronphonon interaction from first principles calculations using density functional theory and boltzmann transport equation to calculate electrical and thermal properties of monolayer snse, sns, ges, gese, sns2, and snse2, at different doping levels, helping evaluate their potential as thermoelectric materials. Here, we investigated the phonon response of few layer bp under uniaxial tensile strain. Introduction to electronphonon interactions youtube. The electron phonon ep interaction and the empirical pseudopotential method for the discussion of the electron phonon interaction it is strictly necessary to count with a satisfactory description of the electronic states as well as the spectrum of vibrations of the solid. The electronphonon interaction, according to the adiabatic approximation volume 51 issue 4 j. Due to this fact, a hot spot turns up, the size of which is much smaller than the phonon mean free path in the silicon layer. Electronphonon interaction and coupled phononplasmon. The electron phonon interaction is expanded in powers of the in teraction which involv es the singleion potential of the electrons in the potential of the ions.
The interest in this problem arises from a variety of physical phenomena such as electrical and thermal resistivities, renormalization of the electronic speci. Electronphonon interactions so far, we considered the motion of electrons in the static periodic potential that would arise if the ions were frozen in their equilibrium positions. Z dr e ikr p v u bk re iqr e ik 0r p v u b 0kr x m z unit cell. Rather, the electronphonon interaction can be expanded in a power series in the scattered wave vector q k. Dermot co ey a dissertation submitted to the faculty of the graduate school of the state. Anisotropic electronphonon interactions in angleresolved.
Electronphonon effects on transport in mesoscopic heterostruct ures. Asymptotic behaviors about the selfenergy of electronphonon interaction cdqz2014selfenergyofelectronphononinteraction. Pdf yangmills structure for electronphonon interactions. His analysis was extended by pines and myself to include coulomb interactions. If the anisotrop y of the sup erconducting gap is ignored or w ashed out b y nonmagnetic impurit y scattering then theory simpli es and t c dep ends on 2 and a single function f whic h is similar to the phonon densit y of states f. Department of energy, division of materials sciences, and the us national science foundation phonons 2010, taipei, taiwan april 17 22, 2010.
In this thesis the ground state electronic properties, lattice dynamics, electronphonon coupling and superconductivity of a variety materials are investigated from first principles. Then we looked just at the ions, and discussed the lattice vibrations phonons while ignoring the existence of valence electrons apart from. Fewlayer black phosphorus bp with an inplane puckered crystalline structure has attracted intense interest for strain engineering due to both its significant anisotropy in mechanical and electrical properties and its high intrinsic strain limit. If the anisotrop y of the sup erconducting gap is ignored or w ashed out b y nonmagnetic impurit y scattering then theory simpli es and t c dep ends on 2 and a single function f whic h is similar to the phonondensit y of states f.
Supporting information the equal footing of thermal. The problem of conventional, lowtemperature superconductivity has been regarded as solved since the seminal work of bardeen, cooper, and schrieffer bcs more than 50 years ago. The unperturbed electron is taken to have freeparticle motion with an effective mass m. The interaction of acoustic phonons and photons in the. We conducted an experimental and computer simula tion study of a singlecrystal metal that monitored and detected directly the changes in the structure during femtosecond heating, as a function of time starting with photonelectron and electron phonon coupling through phononlattice interaction, contraction, melting, nucleation. Let k and bk be the lattice thermal conductance of the system and its modulation due to the electronphonon coupling, respectively.
The electronphonon coupling strength in the spinsplit valence band maximum of singlelayer mos 2 is studied using angleresolved photoemission spectroscopy and density functional theorybased calculations. Twodimensional electron acousticphonon interaction at. The electronphonon interaction in metals nicolas bock october 27, 2003 advisor. The diagrams of electronphonon coupling a general form of dysons equation is derived for electronphonon interaction1. Supporting information on the role of the electronphonon. The electronphonon interaction book chapter iopscience. The electronphonon interaction in disordered systems is due to two process.
They can be viewed as bosonic particles which propagate through the crystal and interact with electrons. The electroiiic problein is solved iteratixdy and tlie phonon population. The integral can now be evaluated by breaking the integral over the whole crystal into a sum of integrals over each individual unit cell. The electronphonon interaction in metals sole distributors for the u. The subtle interplay of electrons and phonons was explained in the. Electronphonon interaction in conventional and unconventional superconductors pegor aynajian auth. Phonon drag is an increase in the effective mass of conduction electrons or valence holes due to interactions with the crystal lattice in which the electron moves. Electronphonon interaction model and thermal transport. Effects of the electronphonon interaction in hexagonal. Electronphonon interaction in a semiconductor is the main factor for relaxation of a transferred electron. The electronphonon interaction from first principles. Then we analyze the role of electronphonon coupling for su perconductivity in the context of the strongcoupling migdaleliashberg theory in some detail. The main point is to realize that the singular behavior is due to the longrange coulomb interaction, which will be screened. While the electronphonon interaction has been studied for almost a century, predictive nonempirical calculations have become feasible only during the past two decades.
There can be acoustic phonon interactions with the electrons, and the optical. The first chapter provides an introduction to the material and concepts of this thesis as well as motivation for the work done herein. Imaging electronphonon interactions a retrospective jim wolfe university of illinois at urbanachampaign research supported by the u. Experimental and simulation study of electron and phonon. The high electron energy induced by the esd in the transistor is transferred to the lattice phonons through electronphonon interaction in the local region of the transistor.