Publications de Luigi Giacomazzi

Partial vibrational density of states for amorphous solids from inelastic neutron scattering

We introduce coherent inelastic neutron scattering with isotope substitution as a technique for measuring site-specific information on the vibrational dynamics of amorphous solids. The technique is used to extract experimentally the partial vibrational den ...

2018

Energy-level alignment in organic dye-sensitized TiO2 from GW calculations

Luigi Giacomazzi, Filippo de Angelis

The electronic energy levels of some representative isolated and oxide-supported organic dyes, relevant for photovoltaic applications, are investigated using many-body perturbation theory within the GW approximation. We consider a set of all-organic dyes ( ...

Amer Inst Physics2013

Medium range structure of tetrahedrally-bonded glasses through the first principles investigation of Raman spectra

Alfredo Pasquarello, Luigi Giacomazzi

We calculate the Raman spectra of vitreous SiO 2 , vitreous GeO 2 , and vitreous GeSe 2 within a density functional scheme. Due to the sensitivity of the Raman spectra to correlations extending beyond the tetrahedral unit, we extract through the comparison ...

2012

Vibrational properties of vitreous GeSe2 with the Becke-Lee-Yang-Parr density functional

Carlo Massobrio, Alfredo Pasquarello, Luigi Giacomazzi

The vibrational properties of vitreous GeSe2 are studied within the Becke-Lee-Yang-Parr (BLYP) generalized gradient approximation to density functional theory. For this purpose, we consider two models. The first one is derived from a chemically ordered net ...

2011

Medium-range structure of vitreous SiO2 obtained through first-principles investigation of vibrational spectra

Alfredo Pasquarello, Paolo Umari, Luigi Giacomazzi

Using a density-functional framework, we investigate the vibrational spectra of vitreous SiO2 to determine to what extent these spectra provide information about the medium-range structure of the oxide network. We carry out a comparative study involving th ...

2009

Vibrational spectra of vitreous SiO2 and vitreous GeO2 from first principles

Alfredo Pasquarello, Luigi Giacomazzi

Using a density-functional approach, we calculate the principal vibrational spectra of vitreous SiO2 and vitreous GeO2 and discuss their analogies and differences. For both glasses, we generate model structures consisting of a random network of corner-shar ...

2007

First principles vibrational spectra of tetrahedrally-bonded glasses : SiO2, GeO2 and GeSe2

Luigi Giacomazzi

Disordered oxides, such as vitreous silica (v-SiO2) and vitreous germania, (v-GeO2) and chalcogenide glasses, such as vitreous germanium diselenide (v-GeSe2) are currently key materials in many technological fields, ranging from Si-based microelectronic to ...

EPFL2007

First-principles investigation of the structural and vibrational properties of vitreous GeSe2

Alfredo Pasquarello, Luigi Giacomazzi

Using a density-functional scheme, we study the structural and vibrational properties of vitreous germanium diselenide (v-GeSe2). Through the use of classical and first-principles molecular-dynamics methods, we generate a set of structural models showing a ...

2007

Vibrational spectra of vitreous germania from first-principles

Alfredo Pasquarello, Luigi Giacomazzi

We report on a first-principles investigation of the structural and vibrational properties of vitreous germania (v-GeO2). Our work focuses on a periodic model structure of 168 atoms, but three smaller models are also studied for comparison. We first carry ...

2006

Medium-range structural properties of vitreous germania obtained through first-principles analysis of vibrational spectra

Alfredo Pasquarello, Luigi Giacomazzi

We analyze the principal vibrational spectra of vitreous GeO2 and derive therefrom structural properties referring to length scales beyond the basic tetrahedral unit. We generate a model structure that yields a neutron structure factor in accord with exper ...

2005