BYVIDYA

MEMRISTOR

Memristor

Memory Resistor+

Memristor

A Memristor is a semiconductor whose resistance varies as a function of flux and charge. This allows it to “remember” what has passed through the circuit.

Characterized by Memristance

Memristance is simply charge-dependent resistance. V(t) = M(q(t))*I(t)

Unit - ohm (Ω)

Symbol

Theory was developed in 1971 by Professor Leon Chua at University of California, Berkeley.

Found while exploring symmetry between the three fundamental passive linear circuit elements.

In 2006, R.Stanley Williams developed practical

model.

Voltage, V (V) – work done required to bring charge from ∞ to a Electric field.

Current, I (A) – flow of electric charge

Flux, Φ(W) – rate of flow through an area

Charge, Q (C) – energy per electron

Current is the derivative of ChargeI=dQ/dt

Voltage is the derivative of Flux V= dΦ/dt

Voltage (V)

Current(i)

Charge (q)

Flux (Φ)

Capacitor,C (F)

Resistor,R (Ω)

Inductor,L (H)

q = C v

Voltage (V)

Current(i)

Charge (q)

Flux (Φ)

q=CvCapacitors q=CvCapacitorsCapacitors

Ohm’s Lawv = R i

Voltage (V)

Current(i)

Charge (q)

Flux (Φ)

Resistors v=Ri

Capacitors q=CvCapacitors

Φ = L i

Voltage (V)

Current(i)

Charge (q)

Flux (Φ)

Φ = Li Inductors

??

v=dΦ/dt i=dq/dt

Resistors v=Ri

q=CvCapacitors

MemristorsΦ=Mq

Voltage (V)

Current(i)

Charge (q)

Flux (Φ)

Φ = Li Inductors

v=dΦ/dt i=dq/dt

Resistors v=Ri

q=CvCapacitors

Φ = M q

dΦ/dt = M(q) dq/dt

V(t) = M(q) I

P = I² M(q)

Retain its resistance level even after power had been shut down.

Remember (or recall) the last resistance it had, before being shut off.

• Applied voltage makes the oxygen vacancies (+ve) to shift towards the –ve voltage.

PT PTTiOv(2-x)

TiO2

3 nm

2 nm

OxidizedReduced

(-)ve (+)ve

Shift between the layers is permanent in nature.

It exist even after the voltage has been removed.

Causes the permanent change in resistance.

A RESISTOR WITH MEMORY BEHAVES LIKE A PIPE

• The diameter of pipe remains same when the current is switched off, until it is switched on again.

• The pipe, when the current is switched on again, remembers what current has flowed through it.

As its effect depends on atomic-scale movements, it only poped up on the nanoscale of William’s devices.

Would allow for a quicker boot up since information is not lost when the device is turned off.

Uses less energy and produces less heat.

Eliminates the need to write computer programs that replicate small parts of the brain.

• Provides greater resiliency and reliability when power is interrupted in data centers.

• Density allows for more information to be stored.

• Power Consumption• As non-volatile memory, memristors do not consume

power when idle.

Conventional devices use only 0 and 1; Memristor can use anything between 0 and 1.

Faster than Flash memory.• Allow digital cameras to take pictures with no delay in

between.

Innovating nanotechnology due to the fact that it performs better the smaller it becomes.

Pattern recognition and learning.

Crossbar latches to replace transistors.

New forms signal processing and control systems.

Memristors can be used to do digital logic using implication instead of NAND.

Though hundreds of thousands of memristor semiconductors have already been built, there is still much more to be perfected.

Needs more defect engineering.

No design standards (rules).