Structural prediction and materials design: from high throughput to global minima optimization methods

In this thesis we use high-throughput techniques and global structure prediction algorithms to predict the crystal structure of different materials under different conditions. We start by investigating the modi cations on the structure of carbon nanotubes under hydrostatic pressure. Afterwards, we explore a subset of ternary silicon clathrates searching for new thermodynamically stable phases. Then, we screen the periodic table for new p−type transparent oxides of the form (Cu, Ag, Au, Ni)XO2 and CuXOS. Finally, we present a new approach for materials design in a pure ab initio way

The crystal structure of p-type transparent conductive oxide CuBO2

We employed ab initio global structural prediction algorithms to obtain the ground-state structure of CuBO2 This is a very promising p-type transparent conductive oxide that was synthesized recently, and thought to belong to the delafossite family. We proved that the true ground state is certainly not the delafossite structure, and that the most promising candidate is a low symmetry monoclinic phase. This is still a layered structure, but with boron and copper having a different coordination with respect to the delafossite phas

From mesoscale to nanoscale mechanics in single-wall carbon nanotubes

The experimental work was carried out in collaboration with W. Wenseleers and S. Cambré at the University of Antwerp, Belgium. The computational results presented have been achieved in part using the Vienna Scientific Cluster (VSC). DJD is grateful for support from the Region Rhône-Alpes through the programme “Accueil-PRO 2014” and from the iMUST Labex programme “Mobility in 2015”. ACTD, TFTC, WC, MALM, SB, DM and ASM acknowledge support from the French Agence Nationale de la Recherche through contract ANR-11-NANO-025 “TRI-CO”. ACTD acknowledges postdoctoral grant from Brazilian Ministry of Education (CAPES)

Pressure-induced radial collapse in few-wall carbon nanotubes: A combined theoretical and experimental study

Brazilian authors acknowledge funding from CNPq (grant 307317/2010-2, INCT NanoBioSimes) and Central Analítica-UFC/CT-INFRA-FINEP/Pró-Equipamentos-CAPES/CNPq-SisNano-MCTI (grant 402284/2013-5). R. S. Alencar is also in debt to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior under the grant No. 99999.004227/2014-00 for financial support. Alexander Soldatov (University of Lulea, Sweden) is warmly acknowledged for discussions on the RBM Raman spectra interpretation at the collapse region