show that polar molecules (water, ammonia, and nitrogen dioxide)
adsorbed solely at the exposed edges of an encapsulated graphene sheet
exhibit ferroelectricity, collectively orienting and switching reproducibly
between two available states in response to an external electric field.
This ferroelectric molecular switching introduces drastic modifications
to the graphene bulk conductivity and produces a large and ambipolar
charge bistability in micrometer-size graphene devices. This system
comprises an experimental realization of envisioned memory capacitive
(“memcapacitive”) devices whose capacitance is a function
of their charging history, here conceived via confined and correlated
polar molecules at the one-dimensional edge of a two-dimensional crystal.
- Graphene edges
- Polar molecules
- Molecular switch