1971

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.