title: A Probabilistic Finite State Logic Machine Realized Experimentally on a Single Dopant Atom.
abstract: Exploiting the potential of nanoscale devices for logic processing requires the implementation of computing functionalities departing from the conventional switching paradigm. We report on the design and the experimental realization of a probabilistic finite state machine in a single phosphorus donor atom placed in a silicon matrix electrically addressed and probed by scanning tunneling spectroscopy (STS). The single atom logic unit simulates the flow of visitors in a maze whose topology is determined by the dynamics of the electronic transport through the states of the dopant. By considering the simplest case of a unique charge state for which three electronic states can be resolved, we demonstrate an efficient solution of the following problem: in a maze of four connected rooms, what is the optimal combination of door opening rates in order to maximize the time that visitors spend in one specific chamber? The implementation takes advantage of the stochastic nature of electron tunneling, while the output remains the macroscopic current whose reading can be realized with standard techniques and does not require single electron sensitivity.
authors.affiliation: Department of Chemistry, B6c, University of Liege , B4000 Liege, Belgium.|Department of Chemical Science, University of Padova , Via Marzolo 1, 35131 Padova, Italy.
authors.forename: Barbara
authors.identifier: 0000-0002-0988-0644
authors.initials: B
authors.lastname: Fresch
authors.affiliation: Centre for Quantum Computation and Communication Technology, School of Physics, The University of New South Wales , Sydney, New South Wales 2052, Australia.
authors.forename: Juanita
authors.initials: J
authors.lastname: Bocquel
authors.affiliation: Centre for Quantum Computation and Communication Technology, School of Physics, The University of New South Wales , Sydney, New South Wales 2052, Australia.
authors.forename: Sven
authors.initials: S
authors.lastname: Rogge
authors.affiliation: The Fritz Haber Center for Molecular Dynamics and Institute of Chemistry, The Hebrew University of Jerusalem , Jerusalem 91904, Israel.|Crump Institute for Molecular Imaging and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine and Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.
authors.forename: R D
authors.initials: RD
authors.lastname: Levine
authors.affiliation: Department of Chemistry, B6c, University of Liege , B4000 Liege, Belgium.
authors.forename: F
authors.identifier: 0000-0001-7434-5245
authors.initials: F
authors.lastname: Remacle
keywords: Single electron device; finite state machine; probabilistic logic; scanning tunneling spectroscopy; single atom transistor; unconventional computing