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 Tools annual

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 Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The recently investigated $1T$-polymorph of monolayer NbSe$_2$ revealed aninsulating behaviour suggesting a star-of-David phase with$\sqrt{13}\,\times\sqrt{13}$ periodicity associated with a Mott insulator,reminiscent of $1T$-TaS$_2$. In this work, we examine this noveltwo-dimensional material from first principles. We find an instability towardsthe formation of an incommensurate charge-density-wave (CDW) and establish thestar-of-David phase as the most stable commensurate CDW. The mottness in thestar-of-David phase is confirmed and studied at various levels of theory: thespin-polarized generalized gradient approximation (GGA) and its extensioninvolving the on-site Coulomb repulsion (GGA+$U$), as well as the dynamicalmean-field theory (DMFT). Finally, we estimate Heisenberg exchange couplings inthis material and find a weak nearest-neighbour ferromagnetic coupling, at oddswith most Mott insulators. We point out the close resemblance between thisstar-of-David phase and flat-band ferromagnetism models.

Charge-density-wave phase, mottness and ferromagnetism in monolayer $1T$-NbSe$_2$