Cluster Mean Field Theory(CMFT) study of frustrated spin systems

Abstract

This project used cluster mean-field (CMFT) to investigate the quantum phase di- agram of different nearest-neighbor and next-nearest neighbor J1-J2 Heisenberg spin lattices and the Shastry-Sutherland Lattice. Different coupling ranges of SSL lattices were explored, including anisotropic dimer interaction, ferromagnetic inter-dimer interactions, and spatially anisotropic frustrations. The main goal of the thesis was to present a comprehensive study and explanation of the presence of fractional mag- netic plateaux phases in the ground state phase diagram of the Shastry-Sutherland lattice under an applied magnetic field at different temperatures in the thermody- namic limit.