title: The straintronic spin-neuron.
abstract: In artificial neural networks, neurons are usually implemented with highly dissipative CMOS-based operational amplifiers. A more energy-efficient implementation is a 'spin-neuron' realized with a magneto-tunneling junction (MTJ) that is switched with a spin-polarized current (representing weighted sum of input currents) that either delivers a spin transfer torque or induces domain wall motion in the soft layer of the MTJ to mimic neuron firing. Here, we propose and analyze a different type of spin-neuron in which the soft layer of the MTJ is switched with mechanical strain generated by a voltage (representing weighted sum of input voltages) and term it straintronic spin-neuron. It dissipates orders of magnitude less energy in threshold operations than the traditional current-driven spin neuron at 0 K temperature and may even be faster. We have also studied the room-temperature firing behaviors of both types of spin neurons and find that thermal noise degrades the performance of both types, but the current-driven type is degraded much more than the straintronic type if both are optimized for maximum energy-efficiency. On the other hand, if both are designed to have the same level of thermal degradation, then the current-driven version will dissipate orders of magnitude more energy than the straintronic version. Thus, the straintronic spin-neuron is superior to current-driven spin neurons.
authors.affiliation: Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, Virginia 23284, USA.
authors.forename: Ayan K
authors.initials: AK
authors.lastname: Biswas
authors.forename: Jayasimha
authors.initials: J
authors.lastname: Atulasimha
authors.forename: Supriyo
authors.initials: S
authors.lastname: Bandyopadhyay
mesh_terms: D000200:Action Potentials; D004560:Electricity; D004735:Energy Transfer; D060328:Magnetic Phenomena; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D008959:Models, Neurological; D008962:Models, Theoretical; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods*; D016571:Neural Networks, Computer; D009474:Neurons / Q000502:physiology*; D013696:Temperature
chemical_list: D058185:Magnetite Nanoparticles