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

We investigate the optical transition selection rules for excitonic Rydbergseries formed in massive Dirac cones. The entanglement of the exciton envelopfunction with the pseudospin texture leads to anomalous selection rules forone-photon generation of excitons, where $d$-orbitals can be excited with theopposite helicity selection rule from the $s$-orbitals in a given valley. Thetrigonal warping effects in realistic hexagonal lattices further renders moreexcited states bright, where $p$-orbitals can also be accessed by one-photonexcitation with the opposite valley selection rules to the $s$-orbitals. Theone-photon generation of exciton in the various states and the intra-excitonictransition between these states are both dictated by the discrete in-planerotational symmetry of the lattices, and our results show that in hexagonal 2Dmaterials the symmetry allowed transitions are enabled when trigonal warpingeffects are included in the massive Dirac fermion model. In monolayertransition metal dichalcogenides where excitons can be generated by visiblelight and intra-excitonic transitions can be induced by infrared light, we givethe strength of these optical transitions, estimated using modifiedhydrogen-like envelope functions combined with the optical transition matrixelements between the Bloch states calculated at various $k$ points.

Optical selection rules for excitonic Rydberg series in the massive Dirac cones of hexagonal 2D materials