<i>In-situ</i> oxygen x-ray absorption spectroscopy investigation of the resistance modulation mechanism in LiNbO2 memristors

Greenlee, Jordan D.; Petersburg, Cole; Calley, W. Laws; Jaye, Cherno; Fischer, Daniel A.; Alamgir, Faisal M.; Doolittle, W. Alan

doi:10.1063/1.4709422

Cited by 31 publications

(30 citation statements)

References 31 publications

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“…To date, there has been only one report on the switching characteristics for the Li‐spinel LiFe 5 O 8 . Besides that, the scarce literature on Li‐based memristor architectures has focused on layered hexagonal Li x CoO 2 , layered LiNbO x and perovskite LiLaTiO 3 …”

mentioning

confidence: 99%

Lithium‐Battery Anode Gains Additional Functionality for Neuromorphic Computing through Metal–Insulator Phase Separation

et al. 2020

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Specialized hardware for neural networks requires materials with tunable symmetry, retention, and speed at low power consumption. The study proposes lithium titanates, originally developed as Li‐ion battery anode materials, as promising candidates for memristive‐based neuromorphic computing hardware. By using ex‐ and in operando spectroscopy to monitor the lithium filling and emptying of structural positions during electrochemical measurements, the study also investigates the controlled formation of a metallic phase (Li7Ti5O12) percolating through an insulating medium (Li4Ti5O12) with no volume changes under voltage bias, thereby controlling the spatially averaged conductivity of the film device. A theoretical model to explain the observed hysteretic switching behavior based on electrochemical nonequilibrium thermodynamics is presented, in which the metal‐insulator transition results from electrically driven phase separation of Li4Ti5O12 and Li7Ti5O12. Ability of highly lithiated phase of Li7Ti5O12 for Deep Neural Network applications is reported, given the large retentions and symmetry, and opportunity for the low lithiated phase of Li4Ti5O12 toward Spiking Neural Network applications, due to the shorter retention and large resistance changes. The findings pave the way for lithium oxides to enable thin‐film memristive devices with adjustable symmetry and retention.

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confidence: 99%

Lithium‐Battery Anode Gains Additional Functionality for Neuromorphic Computing through Metal–Insulator Phase Separation

et al. 2020

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“…Lithium is often deintercalated to form sub-stoichiometric , where the lithium vacancies act as acceptors, lowering the Fermi level inside the valence band [6]. When an electric field is applied, these lithium vacancies freely drift across the material changing the doping profile of the device [10]. The unique physical and electronic structure of lithium niobite affects the radiation damage and recovery mechanisms.…”

Section: Self-healing Of Proton Damage In Lithium Niobite ( ) I Intrmentioning

confidence: 99%

Self-Healing of Proton Damage in Lithium Niobite ( <formula formulatype="inline"><tex Notation="TeX">${\rm LiNbO}_{2}$</tex></formula>)

Shank

Tellekamp

Zhang

et al. 2015

IEEE Trans. Nucl. Sci.

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Proton radiation damage and short-term annealing are investigated for lithium niobite ( ) mixed electronic-ionic memristors. Radiation damage and short-term annealing were characterized using Electrochemical Impedance Spectroscopy (EIS) to determine changes in the device resistance and the lithium ion mobility. The radiation damage resulted in a 0.48% change in the resistance at a fluence of cm . In-situ short-term annealing at room temperature reduced the net detrimental effect of the damage with a time constant of about 9 minutes. The radiation damage mechanism is attributed predominantly to displacement damage at the niobium and oxygen sites trapping lithium ions that are responsible for induced polarization within the material. Short term annealing is attributed to room temperature thermal annealing of these defects, freeing the highly mobile lithium ions.

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“…However, the removal of lithium has been shown to also change the occupation of the bands and thus, two mechanisms for bandstructure modification are possible by removal of Li enhancing its multi-functional utility. 11 Previous work reported more than a two order of magnitude change in resistivity due to changes in lithium content. 2 Additionally, changes in the magnetic moment have been reported, 2 but there is some disagreement about the magnetic nature of lithium niobite in the liturature.…”

Section: Introductionmentioning

confidence: 99%

Evidence of ion intercalation mediated band structure modification and opto-ionic coupling in lithium niobite

Shank

Tellekamp

Doolittle

2015

Journal of Applied Physics

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The theoretically suggested band structure of the novel p-type semiconductor lithium niobite (LiNbO2), the direct coupling of photons to ion motion, and optically induced band structure modifications are investigated by temperature dependent photoluminescence. LiNbO2 has previously been used as a memristor material but is shown here to be useful as a sensor owing to the electrical, optical, and chemical ease of lithium removal and insertion. Despite the high concentration of vacancies present in lithium niobite due to the intentional removal of lithium atoms, strong photoluminescence spectra are observed even at room temperature that experimentally confirm the suggested band structure implying transitions from a flat conduction band to a degenerate valence band. Removal of small amounts of lithium significantly modifies the photoluminescence spectra including additional larger than stoichiometric-band gap features. Sufficient removal of lithium results in the elimination of the photoluminescence response supporting the predicted transition from a direct to indirect band gap semiconductor. In addition, non-thermal coupling between the incident laser and lithium ions is observed and results in modulation of the electrical impedance.

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In-situ oxygen x-ray absorption spectroscopy investigation of the resistance modulation mechanism in LiNbO2 memristors

Cited by 31 publications

References 31 publications

Lithium‐Battery Anode Gains Additional Functionality for Neuromorphic Computing through Metal–Insulator Phase Separation

Lithium‐Battery Anode Gains Additional Functionality for Neuromorphic Computing through Metal–Insulator Phase Separation

Self-Healing of Proton Damage in Lithium Niobite ( <formula formulatype="inline"><tex Notation="TeX">${\rm LiNbO}_{2}$</tex></formula>)

Evidence of ion intercalation mediated band structure modification and opto-ionic coupling in lithium niobite

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