Illustration of Memristor

1971 Memristor

The book of science

Tom Sharp

Leon Chua electromagnetism Illustration of Memristor


A memristor is supposed to remember, even across periods without power, how much current flowed in what direction through it. Thin films of oxygen-depleted titanium dioxide between titanium and platinum electrodes. Doped polymer dielectric-like materials. Thin films of molybdenum oxide and molybdenum disulfide between silver electrodes on a plastic foil. Transition metal dichalcogenide monolayers forming a vertical metal-insulator-metal device. Thin ferroelectric barrier sandwiched between two metallic electrodes. Vertically aligned carbon nanotubes with non-uniform elastic strain and piezoelectric field changes. Movable wall between magnetized domains with different spins. Germanium selenium layers separated by a silver layer with tungsten electrodes. Devices using memristors could replace transistors and, with greater density, speed, and energy economy, form non-volatile dynamic random-access memories.

Non-linear symmetry

The non-linear resistor dynamically relates voltage to current dv = R di The non-linear capacitor dynamically relates charge to voltage dq = C dv The non-linear inductor dynamically relates magnetic flux to current dφ = L di The non-linear memristor must exist to dynamically relate magnetic flux to charge dφ = M dq

Ideal memristor

The ideal memristor will never exist as a working device but inevitably exhibit capacitance and resistance. Similarly, we struggle to relate daily and hourly compromising without abandoning our dreams.

Forty-seven years later, technology companies are still working on ways to commercialize Leon Chua’s invention of the memrister. Some scientists assert that devices that are now in development are not real memristors at all.

See also in The book of science:

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