English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Electron-hole pair excitations in semiconductors have been predicted to beable to give rise to a highly correlated many-body ground state, the excitonicinsulator (EI). Under appropriate conditions below a critical temperature (Tc),strongly bound electron-hole pairs spontaneously form and undergo a phasetransition from a normal band insulator into an exciton condensate,transforming the parent material into a novel correlated insulator. Despiterecent advances in spectroscopic tools, clear direct experimental evidence forthe EI state has been elusive and is often obfuscated by accompanyingelectronic effects. Here we present the reticular bottom-up synthesis of aKagome lattice of [4]triangulene, a two-dimensional (2D) covalent organicframework (COF) imbued with a deliberate excitonic instability excitons withbinding energies larger than the bandgap arising from a pair of flat bands(FBs). Theoretical analyses based on first-principles calculations and scanningtunnelling spectroscopy (STS) reveal quasiparticle spectral signatures mixingvalence (VB) and conduction (CB) characteristics of the FBs along with anon-trivial semiconducting gap that can only be explained by invoking many-bodytheory. Our findings spectroscopically corroborate the nature of a FB inducedexciton insulator ground state and provide a robust yet highly tuneableplatform for the exploration of correlated quasi boson physics in quantummaterials.

Evidence for excitonic insulator ground state in triangulene Kagome lattice