ABSTRACT
Downward scaling of field-effect transistors (FETs) has opened a
new era where transport spectroscopy through one or few atoms
(phosphorus, arsenic, boron, etc.) immersed in a small (silicon)
crystal is achievable. For usual transistors single-dopant effects
are detrimental, leading to an enhanced variability. But the single-
atom transistor (SAT) in which the drain-source current is driven
through gate-controlled atomic orbitals of a dopant opens new
opportunities compared to the usual transistor and even artificial
atom transistors. Large quantization of orbitals for quantum bits
[1] and multivalued logic, single-electron effects for very low-power
applications, information manipulation, and adiabatic transfer [2]
based on charge correlation without charge transfer are examples.
The SAT relies on the bare potential of the donor atom. This potential
is very steep close to the donor’s atom core and less sensitive to
mesoscopic details and therefore to process variability sources.
