Abstract:
The broad aim of this thesis is to study different classes of two-dimensional
(2D) materials using first-principles methods. Surfaces and 2D systems are
interesting for a large number of reasons. Atoms at the surface have reduced
coordination with respect to the bulk, which is responsible for several unusual
phenomena observed only at the surface. Some of these include structural
relaxations and/or reconstructions, mixing of bulk-immiscible metals, enhanced chemical reactivity, high magnetic anisotropy and exotic magnetic
phases such as spin spirals. In this work, I have mainly focused on metallic
surface alloys and interfaces, with a common theme being magnetic materials. We would like to understand various interactions which are dominant
at surfaces and interfaces, and how the interplay between them can lead
to interesting structural, magnetic and electronic properties. Some of the
interactions which are dealt with include elastic, chemical, and magnetic
interactions. This study has allowed us not only to gain insight into the relative importance of these interactions, but also to use our understanding to formulate design principles. Using these principles as a guideline, we have,
e.g., designed a novel surface alloy. In most of my projects, I have worked
alongside an experimental group, and have seen a great synergy between my
theoretical studies and experimental investigations.
