Definition
Plain language
A single one-atom-thick layer of a material.
As stated in the literature
A single atomic-thickness layer of a layered crystal (graphene, hBN, transition metal dichalcogenides), distinguished from bilayer or bulk by characteristic optical contrast.
Also called: monolayers
Why it matters: Monolayers exhibit electronic and optical properties absent in the bulk material, which is the whole point of 2D-materials research.
For example, a single sheet of graphene one carbon atom thick is the monolayer form of graphite.
Heard on the show
“… It invented a precise tilt angle for a molecule far too short to form a stable monolayer, and asserted that roughly eighty-eight kilocalories per mole of condensation energy, comparable …”Episode 240 — Frontier Models Designed Follow-Ups To Fraudulent Papers 93% Of The Time