DOI: 10.5061/dryad.7c41q4c
title: Data from: Synaptic memory devices from CoO/Nb:SrTiO3 junction

description: Non-volatile memristors are promising for future hardware-based
 neurocomputation application because they are capable of emulating
 biological synaptic functions. Various material strategies have been
 studied to pursue better device performance, such as lower energy cost,
 better biological plausibility, etc. In this work, we show a novel design
 for non-volatile memristor based on CoO/Nb:SrTiO3 heterojunction. We found
 the memristor intrinsically exhibited resistivity switching behaviors,
 which can be ascribed to the migration of oxygen vacancies and charge
 trapping and detrapping at the heterojunction interface. The carrier
 trapping/detrapping level can be finely adjusted by regulating voltage
 amplitudes. Gradual conductance modulation can therefore be realized by
 using proper voltage pulse stimulations. And the spike-timing-dependent
 plasticity, an important Hebbian learning rule has been implemented in the
 device. Our results indicate the possibility of achieving artificial
 synapses with CoO/Nb:SrTiO3 heterojunction. Compared with filamentary-type
 of synaptic device, our device has potential to reduce energy consumption,
 realize large scale neuromorphic system, and work more reliably, since no
 structural distortion occurs.
description: Figure 1 Conductance
 characterization of the synaptic deviceElectrical
 characteristics of CoO/Nb:SrTiO3 heterojunctions measured by a Keithley
 2400. Current was applied to the device and voltages were measured. The
 conductance of the device can be calculated.Open_Science_ConductanceCharacterization.xlsxInset of Figure 1(d) The time dependence of the current at the LRS and the fitting curveElectrical characteristics of CoO/Nb:SrTiO3 heterojunctions measured by a Keithley 2400. The time dependence of the current at the LRS was fitted with a bi-exponential relaxation equation.Open_Science_TimeDependenceOfCurrent.xlsxFigure 2(a) Resistance shift in CoO/NSTO deviceThe amplitudes of the stimuli pulses were recorded. The resistance here was calculated by dividing the measured_voltage by measured_current.Open_Science_ResistanceThreshold.xlsxFigure 2(b) Dependence of the device resistance on the pulse amplitude and pulse numberThe device was stimulated by square with varying amplitudes. Pulses were numbered by 1,2,3,....Resistance was measured after each pulse. The resistance recorded here was calculated by dividing the measured_voltage by measured_current.Open_Science_LongTermPotentiation.xlsxFigure 3 Resistance switching cycles and the consecutive positive or negative stimuli pulses.The device was stimulated by step pulses. Pulses were numbered by 1,2,3,.... Resistance was measured after each pulse. The resistance recorded here was calculated by dividing the measured_voltage by measured_current.Open_Science_ResistanceModulation.xlsxFigure4 The STDP response of the electronic synapseThe stimuli spikes were generated by programming a data acquisition card (NI PCI6259) and recorded. The device was stimulated by spike pairs. The resulting timing-dependent resistance modulation was studied by recording the ∆t(spikTimingDifference) and the device conductance change (SynapticWeightChange(%)).Open_Science_STDP.xlsx