Monte Carlo simulations of measured electron energy-loss spectra of diamond and graphite: Role of dielectric-response models

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F17%3A10368804" target="_blank" >RIV/00216208:11320/17:10368804 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.carbon.2017.03.041" target="_blank" >http://dx.doi.org/10.1016/j.carbon.2017.03.041</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.carbon.2017.03.041" target="_blank" >10.1016/j.carbon.2017.03.041</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Monte Carlo simulations of measured electron energy-loss spectra of diamond and graphite: Role of dielectric-response models

Popis výsledku v původním jazyce

In this work we compare Monte Carlo (MC) simulations of electron-transport properties with reflection electron energy-loss measurements in diamond and graphite films. We assess the impact of different approximations of the dielectric response on the observables of interest for the characterization of carbon-based materials. We calculate the frequency-dependent dielectric response and energy-loss functions of these materials in two ways: a full ab initio approach, in which we carry out time-dependent density functional simulations in linear response for different momentum transfers, and a semi-classical model, based on the Drude-Lorentz extension to finite momenta of the optical dielectric function. Ab initio calculated dielectric functions lead to better agreement with measured energy-loss spectra compared to the widely used Drude-Lorentz model. This discrepancy is particularly evident for insulators and semiconductors beyond the optical limit (q not equal 0), where single-particle excitations become relevant. Furthermore, we show that the behaviour of the energy-loss function obtained at different accuracy levels has a dramatic effect on other physical observables, such as the inelastic mean free path and the stopping power in the low energy (&lt;100 eV) regime and thus on the accuracy of MC simulations.

Název v anglickém jazyce

Monte Carlo simulations of measured electron energy-loss spectra of diamond and graphite: Role of dielectric-response models

Popis výsledku anglicky

In this work we compare Monte Carlo (MC) simulations of electron-transport properties with reflection electron energy-loss measurements in diamond and graphite films. We assess the impact of different approximations of the dielectric response on the observables of interest for the characterization of carbon-based materials. We calculate the frequency-dependent dielectric response and energy-loss functions of these materials in two ways: a full ab initio approach, in which we carry out time-dependent density functional simulations in linear response for different momentum transfers, and a semi-classical model, based on the Drude-Lorentz extension to finite momenta of the optical dielectric function. Ab initio calculated dielectric functions lead to better agreement with measured energy-loss spectra compared to the widely used Drude-Lorentz model. This discrepancy is particularly evident for insulators and semiconductors beyond the optical limit (q not equal 0), where single-particle excitations become relevant. Furthermore, we show that the behaviour of the energy-loss function obtained at different accuracy levels has a dramatic effect on other physical observables, such as the inelastic mean free path and the stopping power in the low energy (&lt;100 eV) regime and thus on the accuracy of MC simulations.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10300 - Physical sciences

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2017

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Carbon

ISSN

0008-6223

e-ISSN

—

Svazek periodika

118

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

11

Strana od-do

299-309

Kód UT WoS článku

000401120800035

EID výsledku v databázi Scopus

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