Non-volatile resistive switching, also known as memristor effect,
where an electric field switches the resistance statesof a two-terminal device,
has emerged as an importantconcept in the development of high-density
information storage, computing and reconfigurable systems.
The past decade has witnessed substantial advances in non-volatile
resistive switching materials such as metal oxides and solid electrolytes.
It was long believed that leakage currents would prevent the observation
of this phenomenon for nanometer-thin insulating layers.
However, the recent discovery of non-
volatile resistive switching in two-dimensional monolayers of
transition metal dichalcogenide and hexagonal boron nitride
sandwich structures (also known as atomristors) has refuted this belief
and added a new materials dimension owing to thebenefits of size scaling.
Here we elucidate the origin of the switching mechanism in atomic sheets
using monolayer MoS2as a model system.
Atomistic imaging and spectroscopy reveal that metal substitution
into a sulfur vacancy results in a non-
volatile change in the resistance, which is corroborated by computational
studies of defect structures and electronic states.
These findings provide an atomistic understanding of non-volatile switching
and open a new direction in precicion defect
engineering, down to a single defect, towards achieving
the smallest memritsor for applications in ultra-dense memory,
neuromorphic computing and radio-frequency communication systems.