ELECTRONIC STRUCTURE, MAGNETISM AND TOPOLOGICAL PROPERTIES OF CERTAIN Eu BASED LAYERED MATERIALS

Abstract

This thesis explores the unique characteristics of the materials where electrons ex hibit unconventional behavior, particularly those with linear band dispersion near the Fermi level (FL). The quasi-particle excitations near band crossing points replicate the characteristics of relativistic Dirac or Weyl fermions and demonstrate resistance to perturbations due to the symmetry protection of topology. The intertwining of magnetism with band topology, introduces intriguing electronic band structures with topologically non-trivial properties, often leading to novel magnetic phenomena which have immense potential for applications in spintronics and quantum computing. Mag netism in condensed matter, originating from quantum mechanics, stands as a pivotal domain in both fundamental and applied physics research. The diverse behaviors exhibited by magnetic materials in response to external magnetic fields underpin es sential applications in devices like magnetic memory, spintronics, giant magnetore sistance, and beyond. In solids, the cornerstone of magnetism lies in ions harboring unpaired electrons, characterized by non-zero magnetic moments. These ions exhibit markedly distinct phenomena when they are in proximity and able to interact with each other, in contrast to their behavior when isolated or non-interacting. This un derscores the diverse range of magnetic moment interactions, specifically exchange interactions, which give rise to the myriad of magnetic properties observed in solids.