STM driven transition from rippled to buckled graphene in a spin-membrane model

TL;DR

This paper models rippling and buckling transitions in graphene using a spin-membrane approach, revealing phase behavior and nonequilibrium effects relevant to STM experiments.

Contribution

It introduces a simple spin-membrane model to describe phase transitions in graphene, including nonequilibrium dynamics under STM-like conditions.

Findings

Transition from rippled to buckled graphene depends on temperature and spin coupling.

Reversible and irreversible phase transitions observed under different STM currents.

Model explains recent experimental observations of graphene behavior.

Abstract

We consider a simple spin-membrane model for rippling in graphene. The model exhibits transitions from a flat but rippled membrane to a buckled one. At high temperature the transition is second order but it is first order at low temperature for appropriate strength of the spin-spin coupling. Driving the system across the first order phase transition in nonequilibrium conditions that mimic interaction of the graphene membrane with a STM tip explains recent experiments. In particular, we observe a reversible behavior for small values of the STM current and an irreversible transition from flat rippled membrane to rigid buckled membrane when the current surpasses a critical value. This work opens the possibility to test mechanical properties of graphene under different temperature and electrostatic conditions.