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

In a recent work, new two-dimensional materials, the monolayerMoSi$_{2}$N$_{4}$ and WSi$_{2}$N$_{4}$, have been successfully synthesized inexperiment, and several other monolayer materials with the similar structure,such as MoSi$_{2}$As$_{4}$, have been predicted [{\color{blue}Science 369,670-674 (2020)}]. Here, based on first-principles calculations and theoreticalanalysis, we investigate the electronic and optical properties of monolayerMoSi$_{2}$N$_{4}$, WSi$_{2}$N$_{4}$ and MoSi$_{2}$As$_{4}$. We show that thesematerials are semiconductors, with a pair of Dirac-type valleys located at thecorners of the hexagonal Brillouin zone. Due to the broken inversion symmetryand the effect of spin-orbit coupling, the valley fermions manifest spin-valleycoupling, valley-contrasting Berry curvature, and valley-selective opticalcircular dichroism. We also construct the low-energy effective model for thevalleys, calculate the spin Hall conductivity and the permittivity, andinvestigate the strain effect on the band structure. Our result revealsinteresting valley physics in monolayer MoSi$_{2}$N$_{4}$, WSi$_{2}$N$_{4}$ andMoSi$_{2}$As$_{4}$, suggesting their great potential for valleytronics andspintronics applications.

Valley-dependent properties of monolayer MoSi$_{2}$N$_{4}$, WSi$_{2}$N$_{4}$ and MoSi$_{2}$As$_{4}$