Memristor Non-linear symmetry Ideal memristor Commentary

Leon Chua electromagnetism

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.