title: Learning through ferroelectric domain dynamics in solid-state synapses.
abstract: In the brain, learning is achieved through the ability of synapses to reconfigure the strength by which they connect neurons (synaptic plasticity). In promising solid-state synapses called memristors, conductance can be finely tuned by voltage pulses and set to evolve according to a biological learning rule called spike-timing-dependent plasticity (STDP). Future neuromorphic architectures will comprise billions of such nanosynapses, which require a clear understanding of the physical mechanisms responsible for plasticity. Here we report on synapses based on ferroelectric tunnel junctions and show that STDP can be harnessed from inhomogeneous polarization switching. Through combined scanning probe imaging, electrical transport and atomic-scale molecular dynamics, we demonstrate that conductance variations can be modelled by the nucleation-dominated reversal of domains. Based on this physical model, our simulations show that arrays of ferroelectric nanosynapses can autonomously learn to recognize patterns in a predictable way, opening the path towards unsupervised learning in spiking neural networks.
authors.affiliation: Unité Mixte de Physique, CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, Palaiseau 91767, France.
authors.forename: Sören
authors.initials: S
authors.lastname: Boyn
authors.affiliation: Unité Mixte de Physique, CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, Palaiseau 91767, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Grollier
authors.affiliation: University of Bordeaux, IMS, UMR 5218, Talence F-33405, France.
authors.forename: Gwendal
authors.initials: G
authors.lastname: Lecerf
authors.affiliation: Department of Physics and Institute for Nanoscience and Engineering, University of Arkansas Fayetteville, Arkansas 72701, USA.
authors.forename: Bin
authors.identifier: 0000-0002-0107-0727
authors.initials: B
authors.lastname: Xu
authors.affiliation: Centre de Nanosciences et de Nanotechnologies, CNRS, Univ. Paris Sud, Université Paris-Saclay, C2N-Orsay, Orsay cedex 91405, France.
authors.forename: Nicolas
authors.identifier: 0000-0003-1966-5195
authors.initials: N
authors.lastname: Locatelli
authors.affiliation: Unité Mixte de Physique, CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, Palaiseau 91767, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Fusil
authors.affiliation: Unité Mixte de Physique, CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, Palaiseau 91767, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Girod
authors.affiliation: Unité Mixte de Physique, CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, Palaiseau 91767, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Carrétéro
authors.affiliation: Unité Mixte de Physique, CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, Palaiseau 91767, France.
authors.forename: Karin
authors.initials: K
authors.lastname: Garcia
authors.affiliation: Thales Research and Technology, 1 Avenue Augustin Fresnel, Campus de I'Ecole Polytechnique, Palaiseau 91767, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Xavier
authors.affiliation: University of Bordeaux, IMS, UMR 5218, Talence F-33405, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Tomas
authors.affiliation: Department of Physics and Institute for Nanoscience and Engineering, University of Arkansas Fayetteville, Arkansas 72701, USA.
authors.forename: Laurent
authors.initials: L
authors.lastname: Bellaiche
authors.affiliation: Unité Mixte de Physique, CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, Palaiseau 91767, France.
authors.forename: Manuel
authors.initials: M
authors.lastname: Bibes
authors.affiliation: Unité Mixte de Physique, CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, Palaiseau 91767, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Barthélémy
authors.affiliation: University of Bordeaux, IMS, UMR 5218, Talence F-33405, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Saïghi
authors.affiliation: Unité Mixte de Physique, CNRS, Thales, Univ. Paris Sud, Université Paris-Saclay, Palaiseau 91767, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Garcia
mesh_terms: D004560:Electricity; D007501:Iron / Q000737:chemistry*; D016571:Neural Networks, Computer; D013997:Time Factors
chemical_list: D007501:Iron