Mémoires de Fin d’Etudes
Etablissement
Université de Laghouat – Amar Telidji
Affiliation
Département Physique
Auteur
DJAILI, Salim
Directeur de thèse
GUEDDIM Ahmed (Maitre de conférence)
Co-directeur
GUBADJ Djamel Abdenacer (Maitre de conférence)
Filière
Physique des Matériaux
Diplôme
Doctorat
Titre
Molecular Dynamics Investigations of the Structural, Elastic and Thermodynamic Properties of Cadmium/Magnesium Oxide
Mots clés
Structural, elastic, thermodynamic properties, molecular dynamics, (Mg/Cd)O
Résumé
Cadmium oxide is a II–VI compound semiconductor consisting of cadmium from group II and oxygen from group VI in the periodic table of elements [1,2]. The different structured CdO materials are now widely used as transparent conductive oxides (TCO) in various physical applications [3], specifically in optoelectronic devices such as solar cells because of its high transparency in the visible region of the solar spectrum [4]. These materials are also used in diodes, gas sensors and transparent electrodes [5]. CdO has a narrow direct bandgap ranging from 2.2eV to 2.5eV [6]. In addition, it has several attractive properties, such as low resistivity, high density, high melting point, and has a cubic crystal structure with lattice constant of 0.4695nm [7]. Magnesium oxide (MgO) is a versatile material. It is formed by an ionic bond between one magnesium and one oxygen atom. It is used in residential and commercial building construction. It is suitable for wide range of applications, where it can be used as an insulator in industrial cables, a basic refractory material for crucibles, a principal ingredient in construction materials used for fireproofing, and a supplement to maintain adequate magnesium in the body [8]. Furthermore, MgO is used as an insulator in devices that exhibit the tunnel magneto-resistance effect [9]. The structural and thermodynamic properties of material under high pressure, both experimentally and theoretically, have received considerable attention in recent years [1,2]. The reason is that the exploration of the physical and chemical properties of material at high pressure is of a remarkably interdisciplinary interest. Molecular dynamics (MD) simulation technique is a very strong tool in the study and prediction of the materials dynamics and their subsequent physical properties. However, the accuracy of such MD predictions depends significantly on the chosen interatomic potential used in the simulations. Various embedded atom method (EAM) potentials were developed in the past two decades, which are extensively used in studying the materials physical properties. In the present work, we intend to study the structural, elastic and thermodynamic properties of cadmium/magnesium oxide from molecular dynamics algorithms using classical and recently developed interactomic potentials. Note that using such simulations, one can extend the investigation of the desired properties to non-zero temperatures bearing in mind that ab initio calculations are performed particularly for zero-temperature state. In addition, they are time consuming and computing costly.
Statut
Validé