Mechanical anisotropy and multiple direction-dependent Dirac states in a synthesized Ag3C20 monolayer

Recently, a two-dimensional (2D) orthorhombic silver-organic framework, Ag3C20 monolayer, was synthesized by assembling organic molecules linked with multiple aryl-metal bonds. Using first-principles calculation, herein we demonstrate that, owing to the unique bonding feature, Ag3C20 monolayer not only exhibits strong mechanical anisotropy, but also possesses rich orientation-dependent Dirac states allowing for modulation via external means. Around the Fermi level below, the intrinsic Dirac points form two quasi-type-III nodal lines protected by mirror symmetry, which can further evolve into hybrid nodal loops under tiny strains. Intriguingly, a peculiar semi-Dirac state near the Fermi level above emerges under a critical strain by merging two type-I Dirac cones, which harbors direction-dependent strongly localized fermions, normal massive carries, and ultrafast Dirac fermions at the same time. These findings suggest that the mechanically sensitive Ag3C20 monolayer is a promising 2D material to realize the interesting Dirac physics and multiple carrier transport with high anisotropy.

Automated summary

A two-dimensional orthorhombic silver-organic framework, Ag3C20 monolayer, has been synthesized and shown to exhibit strong mechanical anisotropy and rich orientation-dependent Dirac states. It can undergo different spin-orbit structural changes under different strains, including spin-orbit lines and semi-spin-orbit states. These characteristics make Ag3C20 monolayer a promising 2D material with potential for interesting spin-orbit physics and multi-carrier transport.