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/

Zendy Plus

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

Zendy Tools

Zendy Open

We investigate two-photon transitions to the electron-hole scatteringcontinuum in monolayer transition-metal dichalcogenides, and identify twocontributions to this nonlinear optical process with opposite circularlypolarized valley selection rules. In the non-interacting limit, the competitionbetween the two contributions leads to a crossover of the selection rule withthe increase of the two-photon energy. With the strong Coulomb interactionbetween the electron and hole, the two contributions excite electron-holescattering states in orthogonal angular momentum channels, while the strengthof the transition can be substantially enhanced by the interaction. Based onthis picture of the two-photon transition, the second harmonic generation (SHG)in the electron-hole continuum is analyzed, where the Coulomb interaction isshown to greatly alter the relative strength of different cross-circularpolarized SHG processes. Valley current injection by the quantum interferenceof one-photon and two-photon transition is also investigated in the presence ofthe strong Coulomb interaction, which significantly enhances the injectionrate.

Nonlinear optics in the electron-hole continuum in 2D semiconductors: two-photon transition, second harmonic generation and valley current injection