Spontaneous symmetry breaking during the switching of a buckled graphene membrane

Switching between the states of a buckled graphene membrane for non-volatile memory applications has been studied. The structure of a zigzag graphene strip bent by a force applied to the central region has been investigated by means of the density functional theory with the use of a B3LYP/6-31G approximation. The initial state of the buckled graphene membrane has the geometry of a segment of a half of a (20,0) carbon nanotube with a length of 5 hexagons. The force has been simulated by sequential displacement of the central atoms of the strip toward the fixed edges of the structure. The dependences of the deformation energy and internal forces on the positions of central atoms have been found. Spontaneous breaking of the membrane symmetry decreasing the energy threshold between the states has been discovered.