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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Topological metals with protected band-crossing points have been attractinggreat interest. Here we report novel topological band features in a family ofmetal diboride materials. Using first- principles calculations, we show thatthese materials are metallic, and close to Fermi level, there appearscoexistence of one pair of nodal rings and one pair of triply-degenerate nodalpoints (TNPs). The nodal ring here is distinct from the previously studied onesin that its formation requires four entangled bands, not just two as inprevious cases, hence it is termed as a four-band nodal ring (FNR). Remarkably,we show that FNR features Dirac-cone-like surface states, in contrast to theusual drumhead surface states for two-band nodal rings. Due to the presence ofinversion symmetry, the TNP here is also different from those discussedpreviously in inversion-asymmetric systems. Especially, when spin-orbitcoupling is included, the TNP here transforms into a novel Dirac point that isclose to the borderline between the type-I and type-II Dirac point categories.We discuss their respective symmetry protections, and construct effectivemodels for their characterization. The large linear energy range (> 2 eV) inthese materials should facilitate the experimental detection of the signaturesof these nontrivial band crossings.

Coexistence of four-band nodal rings and triply-degenerate nodal points in centrosymmetric metal diborides