posted on 2022-12-19, 19:35authored byQingzhong Gui, Zhen Wang, Zhaofu Zhang, Liu Xie, Xiaoming Zha, Jun Wang, Yuzheng Guo
Atomically thin two-dimensional (2D) materials have attracted
tremendous
interest and shown great potential in various research areas of modern
nanotechnology. Here, we systematically study a category of 2D families,
namely, graphene-like monolayer monoxides, monochlorides, and mononitrides
(GLMMs), by virtue of density functional theory and density functional
perturbation theory. First, the stability of different native point
defects in GLMMs is investigated energetically, and the results show
that most vacancy defects, especially the neutral nonmetal atom vacancies,
possess high formation energy, manifesting their outstanding structural
stability and high resistance to vacancy formation during the preparation
process. The ab initio molecular dynamics also confirm the thermal
stability of these GLMMs with and without defects. Subsequently, their
dielectric properties are explored by the effective dielectric model
(EDM) and 2D electronic polarizability simultaneously for comparison.
It is found that most GLMMs possess far higher out-of-plane dielectric
constants than h-BN, behaving as promising monolayer materials for
device applications. Moreover, 2D electronic polarizability is proven
to exhibit a significant advantage in evaluating the dielectric property
of 2D materials with an atomically thin layer over the EDM method,
owing to the sensitivity of the EDM on the layer thickness. All theoretical
calculation results provide a comprehensive prediction of the atomic
structures and dielectric properties of GLMMs, aiming to facilitate
the synthesis and further application of such novel 2D materials.