Stability of Planar Slits in Multilayer Graphite Crystals

TL;DR

This study uses a coarse-grained model to analyze the stability of planar slits in multilayer graphite, revealing critical widths for open and closed states and their dependence on layer number and temperature.

Contribution

It introduces a new simulation approach to determine the stability conditions of slits in multilayer graphite based on layer number and thermal effects.

Findings

Open slit stability depends on cavity width and layer number.

Critical width for open slits increases with the number of layers.

Thermal oscillations can induce transitions from open to closed states at high temperatures.

Abstract

Using a two-dimensional coarse-grained chain model, planar slits in multilayer graphite crystals are simulated. It is shown that when covering a linear cavity on the flat surface of a graphite crystal with a multilayer graphene sheet, an open (unfilled slit) can form only if the cavity width does not exceed a critical value L_o (for width L>L_o, only a closed state of the slit is formed, with the cavity space filled by the covering sheet). The critical width of the open slit L_o increases monotonically with the number of layers K in the covering sheet. For a single-layer cavity, there is a finite critical value of its width L_o<3nm, while for two- and three-layer cavities, the maximum width of the open slit increases infinitely with increasing K as a power function K^\alpha with exponent 0<\alpha<1. Inside the crystal, two- and three-layer slits can have stable open states at any width. For a slit with width L>7.6nm, a stationary closed state is also possible, in which its lower and upper surfaces adhere to each other. Simulation of thermal oscillations showed that open states of two-layer slits with width L<15nm are always stable against thermal oscillations, while wider slits at T>400K transition from the open to the closed state. Open states of three-layer slits are always stable against thermal oscillations.