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

We have considered non-magnetic materials with weak spin-orbit coupling, thatare periodic in two non-collinear directions, and finite in third, orthogonaldirection. In some cases, combined time-reversal and crystal symmetry of suchsystems, allows the existence of Dirac cones at certain points in thereciprocal space. We have investigated in a systematic way, all points ofBrillouin zone of all 80 diperiodic groups and have found sufficient conditionsfor the existence of s=1/2 Dirac fermions, with symmetry-provided band touchingat the vertex of the Dirac cones. Conversely, complete linear dispersion isforbidden for orbital wave-functions belonging to two-dimensional irreduciblerepresentations (irreps) of little groups that do not satisfy certaingroup-theoretical conditions given in this paper. Our results are illustratedby a tight-binding example.

Existence of Dirac cones in Brillouin zone of diperiodic atomic crystals according to group theory