PIRSA:19070086

Stable Flat Bands, Topology, and Superconductivity of Magic Honeycomb Network

Cho, G.Y. (2019). Stable Flat Bands, Topology, and Superconductivity of Magic Honeycomb Network. Perimeter Institute. https://pirsa.org/19070086

Cho, Gil Young. Stable Flat Bands, Topology, and Superconductivity of Magic Honeycomb Network. Perimeter Institute, Jul. 30, 2019, https://pirsa.org/19070086 

          @misc{ pirsa_PIRSA:19070086,
            doi = {10.48660/19070086},
            url = {https://pirsa.org/19070086},
            author = {Cho, Gil Young},
            keywords = {Condensed Matter},
            language = {en},
            title = {Stable Flat Bands, Topology, and Superconductivity of Magic Honeycomb Network},
            publisher = {Perimeter Institute},
            year = {2019},
            month = {jul},
            note = {PIRSA:19070086 see, \url{https://pirsa.org}}
          }

Gil Young Cho Pohang University of Science and Technology

DOI 10.48660/19070086
Collection
Talk Type Scientific Series
Subject

Abstract

We uncover a rich phenomenology of the self-organized honeycomb network superstructure of one-dimensional metals in a nearly-commensurate charge-density wave 1T-TaS${}_2$, which may play a significant role in understanding global topology of phase diagrams and superconductivity. The key observation is that the emergent honeycomb network magically supports a cascade of flat bands, whose unusual stability we thoroughly investigate. Furthermore, by combining the weak-coupling mean-field and strong-coupling approaches, we argue that the superconductivity will be strongly enhanced in the network. This provides a natural cooperative mechanism of the charge order and superconductivity, which coexist side-by-side in the 1T-TaS${}_2$. Not only explaining the superconductivity, we show that abundant topological band structures including several symmetry-protected band crossings and corner states, which are closely related to that of the higher-order topology, appear. The results reported here can be generically applicable to various other systems with similar network superstructures.