Browsing NTNU Open by Author "Akola, Jaakko"
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Atomistic simulations of early stage clusters in Al-Mg alloys
Kleiven, David; Ødegård, Olve Lyngved; Laasonen, Kari; Akola, Jaakko (Peer reviewed; Journal article, 2019)The Cluster Expansion formalism based on Density Functional Theory (DFT) simulation data has been applied for AlMg alloys with high accuracy ( meV/atom). The atomistic simulations are used to model the AlMg phase diagram, ... -
Atomistic simulations of early stage clusters in AlMg alloys
Kleiven, David; Akola, Jaakko; Ødegård, Olve Lyngved; Laasonen, Kari (Journal article; Peer reviewed, 2018)The Cluster Expansion formalism based on Density Functional Theory (DFT) simulation data has been applied for AlMg alloys with high accuracy ( meV/atom). The atomistic simulations are used to model the AlMg phase diagram, ... -
Atomistic simulations of thermodynamics and dissolution of iron-silicon phases in iron encasements
Tranås, Rasmus André (Master thesis, 2019)Målet med denne masteroppgaven er å bruke tetthets-funksjonal-teori sammen med en cluster-ekspansjons-metode, slik at jern-silisium legeringer på et statisk kubisk romsentrert gitter kan bli studert ved bruk av Monte ... -
CLEASE: a versatile and user-friendly implementation of cluster expansion method
Chang, Jin Hyun; Kleiven, David; Melander, Marko; Akola, Jaakko; Garcia-Lastra, Juan Maria; Vegge, Tejs (Journal article; Peer reviewed, 2019)Materials exhibiting a substitutional disorder such as multicomponent alloys and mixed metal oxides/oxyfluorides are of great importance in many scientific and technological sectors. Disordered materials constitute an ... -
Combined experimental and theoretical study of acetylene semi-hydrogenation over Pd/Al <sub>2</sub> O <sub>3</sub>
Goncalves, Liliana PL; Wang, Jianguang; Vinati, Simone; Barborini, Emanuele; Wei, Xian-Kui; Heggen, Marc; Franco, Miguel; Sousa, Juliana PS; Petrovykh, Dmitri Y; Soares, Olívia Salomé Gonçalves Pinto; Kovnir, Kirill; Akola, Jaakko; Kolen'ko, Yury V (Peer reviewed; Journal article, 2019)The semi-hydrogenation of acetylene (C2H2 + H2 = C2H4, ΔH = −172 kJ mol−1) is a well-studied reaction that is important for purification of ethylene, C2H4, feed used in polyethylene production. Pd-based catalysts are most ... -
Comparison of optical response from DFT random phase approximation and a low-energy effective model: Strained phosphorene
Alidoust, Mohammad; Isachsen, Erlend E; Halterman, Klaus; Akola, Jaakko (Peer reviewed; Journal article, 2021)The engineering of the optical response of materials is a paradigm that demands microscopic-level accuracy and reliable predictive theoretical tools. Here we compare and contrast the dispersive permittivity tensor, using ... -
Conductivity control via minimally invasive anti-Frenkel defects in a functional oxide
Evans, Donald; Holstad, Theodor Secanell; Mosberg, Aleksander Buseth; Småbråten, Didrik Rene; Vullum, Per Erik; Dadlani, Anup; Shapovalov, Konstantin; Yan, Zewu; Bourret, Edith; Gao, David Zhe; Akola, Jaakko; Torgersen, Jan; Van Helvoort, Antonius; Selbach, Sverre Magnus; Meier, Dennis (Peer reviewed; Journal article, 2020)Utilizing quantum effects in complex oxides, such as magnetism, multiferroicity and superconductivity, requires atomic-level control of the material’s structure and composition. In contrast, the continuous conductivity ... -
Density functional simulations of a conductive bridging random access memory cell: Ag filament formation in amorphous GeS2
Akola, Jaakko; Konstantinou, Konstantinos; Jones, R.O. (Peer reviewed; Journal article, 2022)Density functional/molecular dynamics simulations have been performed to shed light on the drift of Ag atoms in an amorphous Ge S 2 solid-state electrolyte between Ag and Pt electrodes in the presence of a finite ... -
Density functional simulations of pressurized Mg-Zn and Al-Zn alloys
Alidoust, Mohammad; Kleiven, David; Akola, Jaakko (Peer reviewed; Journal article, 2020)Binary Mg-Zn and Al-Zn alloys have been investigated theoretically under static isotropic pressure. The stable phases of these binaries on both initially hexagonal-close-packed (hcp) and face-centered-cubic (fcc) lattices ... -
Dielectric Response of Phosphorene Subject to Strain
Isachsen, Erlend Elias (Master thesis, 2021)I denne avhandlingen presenteres en teoretisk studie av den dielektriske responsen for det to-dimensjonale (2D) materialet fosforén utsatt for deformasjon, med utgangspunkt i en effektiv lav-energi k∙p Hamilton-operator. ... -
The effect of natural ageing on clustering and precipitation in heat-treatable aluminium alloys
Thronsen, Elisabeth (Doctoral theses at NTNU;2022:274, Doctoral thesis, 2022)The consumption volume of aluminium (Al) alloys is expected to increase in the coming years. They are typically used in the automotive industry, where light-weighting has become a major design consideration to save fuel, ... -
Electric-field-induced annihilation of localized gap defect states in amorphous phase-change memory materials
Konstantinou, Konstantinos; Mocanu, Felix C.; Akola, Jaakko; Elliott, Stephen R. (Peer reviewed; Journal article, 2022)Structural relaxation of amorphous phase-change-memory materials has been attributed to defect-state annihilation from the band gap, leading to a time-dependent drift in the electrical resistance, which hinders the development ... -
Electron localization in recrystallized models of the Ge2Sb2Te5 phase-change memory material
Konstantinou, Konstantinos; Mocanu, Felix C.; Akola, Jaakko (Peer reviewed; Journal article, 2022)Understanding the relation between the structural disorder in the atomic geometry of the recrystallized state of phase-change memory materials and the localized states in the electronic structure is necessary not only for ... -
En DFT analyse på kobber basert metallisk-organisk dekomponerings blekk
Roven, Henrik (Master thesis, 2020)En ny generasjon av kobber basert elektronisk blekk har blitt nylig utviklet som dekomponeres til metallisk kobber under varme. Blekkene er basert på kobber format komplekser i en +2 oksidasjonstall, som reduseres til en ... -
Generalization of the Recursive Green's Function Approach to Spin-Orbit Coupled Graphene
Hallaråker, Magnus Halvor (Master thesis, 2021)I denne avhandlingen har vi generalisert den Rekursive Green’s Funksjons-metoden for å studere ladning- og spinnstrømmer samt deres romfordeling i nanoflak av grafen. For å kunne simulere et realistisk system hvor ... -
Highly ductile amorphous oxide at room temperature and high strain rate
Frankberg, Erkka J.; Kalikka, Janne; García Ferré, Francisco; Joly- Pottuz, Lucile; Salminen, Turkka; Hintikka, Jouko; Hokka, Mikko; Koneti, Siddardha; Douillard, Thierry; Le Saint, Bérangère; Kreiml, Patrice; Cordill, Megan J.; Epicier, Thierry; Stauffer, Douglas; Vanazzi, Matteo; Roiban, Lucian; Akola, Jaakko; Di Fonzo, Fabio; Levänen, Erkki (Journal article; Peer reviewed, 2019)Oxide glasses are an integral part of the modern world, but their usefulness can be limited by their characteristic brittleness at room temperature. We show that amorphous aluminum oxide can permanently deform without ... -
Inherent electron and hole trapping in amorphous phase-change memory materials: Ge<inf>2</inf>Sb<inf>2</inf>Te<inf>5</inf>
Konstantinou, Konstantinos; Elliott, Stephen R.; Akola, Jaakko (Peer reviewed; Journal article, 2022)While the amorphous state of a chalcogenide phase-change material is formed inside an electronic-memory device via Joule heating, caused by an applied voltage pulse, it is in the presence of excess field-induced electrons ... -
Josephson effect in graphene bilayers with adjustable relative displacement
Alidoust, Mohammad; Jauho, Anti-pekka; Akola, Jaakko (Peer reviewed; Journal article, 2020)The Josephson current is investigated in a superconducting graphene bilayer where pristine graphene sheets can make in-plane or out-of-plane displacements with respect to each other. The superconductivity can be of an ... -
Kinetic Monte Carlo simulations of the early stages of precipitation in Al-Mg-Si alloys using ab initio based activation energies
Nygård, Øystein Tormodsen (Master thesis, 2020)Kinetisk Monte Carlo simuleringer har blitt utført med bruk av to ulike uttrykk for aktiveringsenergiene med hensikt til å få bedre innsikt i kinetikken i den tidlige fasen av presipitering i Al-Mg-Si legeringer på atomnivå. ... -
Machine-learned model Hamiltonian and strength of spin–orbit interaction in strained Mg2X (X = Si, Ge, Sn, Pb)
Alidoust, Mohammad; Rothmund, Erling Velten; Akola, Jaakko (Peer reviewed; Journal article, 2022)Machine-learned multi-orbital tight-binding (MMTB) Hamiltonian models have been developed to describe the electronic characteristics of intermetallic compounds Mg2Si, Mg2Ge, Mg2Sn, and Mg2Pb subject to strain. The MMTB ...