The Role of Carbonaceous Material in the Formation of Macraes Orogenic Gold Deposit, New Zealand

The PhD project investigated the role of carbonaceous material in the formation of Macraes orogenic gold deposits. It provided the first evidence that in-situ carbonaceous material directly contributes to Au incorporation into polyframboids which may provide the source of Au for the Macraes gold deposit; that carbonaceous material in mineralized rocks of gold deposit is most likely hydrothermally deposited and contributes to Au precipitation indirectly; and that dodecanethiol may transport Au in hydrothermal systems

Coupled topological flat and wide bands: Quasiparticle formation and destruction

Flat bands amplify correlation effects and are of extensive current interest. They provide a platform to explore both topology in correlated settings and correlation physics enriched by topology. Recent experiments in correlated kagome metals have found evidence for strange-metal behavior. A major theoretical challenge is to study the effect of local Coulomb repulsion when the band topology obstructs a real-space description. In a variant to the kagome lattice, we identify an orbital-selective Mott transition for the first time in any system of coupled topological flat and wide bands. This was made possible by the construction of exponentially localized and Kramers-doublet Wannier functions, which in turn leads to an effective Kondo lattice description. Our findings show how quasiparticles are formed in such coupled topological flat-wide band systems and, equally important, how they are destroyed. Our work provides a conceptual framework for the understanding of the existing and emerging strange-metal properties in kagome metals and beyond.Comment: 30 pages, 6 figures. To appear in Science Advance