First-principles studies of electron-phonon induced superconductivity and beyond

The prospect of precisely predicting the behavior of solids entirely by means of theory and computations is enticing. This dissertation presents the results of the application of the first-principles physical approaches to study superconductivity in a set of materials. In the first chapter a brief overview of the key concepts used in this manuscript in given. A description of the theoretical methodology and the key computational techniques used in this work constitute the subject of chapter 2. Studies of class-I/conventional and class-II/non-conventional superconducting materials are contained in chapters 3 and 4 respectively. In particular, precise calculations of the electron-phonon interaction and superconducting parameters of elemental lithium at ambient conditions and under pressure and lithium-intercalated borocarbide compounds are presented. In addition, the application of first-principle techniques to study iron selenide in multiple configurations is given. A discussion of superconductivity in complex oxides is presented in chapter 5 with emphasis on the importance of oxygen octahedra tilts. And, finally, concluding remarks from the author are given in the last chapter.