Transcript Memristors by Quantum Mechanics

Quantum Mechanics and
Nanoelectronics
Thomas Prevenslik
QED Radiations
Discovery Bay, Hong Kong
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Introduction
Nanoelectronics became popularized by Chua in 1971
claiming [1] a circuit element existed having a resistance that
depended on the time–integral of the current.
Based on symmetry arguments, electronics based on the
resistor, capacitor, and inductor was considered incomplete.
For completeness, Chua proposed a fourth element:
Memristor
[1] L. O. Chua, “Memristor - the missing circuit element,”
IEEE Trans. Circuit Theory, vol. 18, pp. 507–519, 1971.
ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
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Background
Chua lacked a working prototype, and the memristor lay
dormant for almost 40 years
In 2008, a group at Hewlett-Packard (HP) developed [2] a
memristor comprising a thin film of TiO2 sandwiched between
Pt electrodes.
2. D. B. Strukov, et al., “The missing memristor found,” Nature 453, 7191 (2008).
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
HP Memristor
The memristor is basically a variable resistor dependent on the
current I that flows by the amount of charge Q transferred.
Q =  I dt
HP claims the charge is caused by oxygen vacancies in the TiO2
that act as positive charge holes moving under the bias voltage
that change the memristor resistance during the cycle
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Problem
Memristor behavior is found without oxygen vacancies in
molecular layers between gold electrodes and in single
materials without electrodes, e.g., silicon nanowires
Lacking vacancies, explanations of memristor behavior assume
the presence of space charge, but the mechanism by which the
space charge is produced is not identified.
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Observations
Memristor behavior only observed at the nanoscale.
(Thin films, nanowire, etc)
At the macroscale, memristors behave like ordinary resistors
where resistance is voltage divided by current.
The observations suggest a QM size effect
QM = Quantum Mechanics
ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
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Space Charge
In this talk I will convince you that QM creates charge Q anytime
EM energy is absorbed at the nanoscale
For memristors, the EM energy is Joule heating.
But QM requires the heat capacity of the thin film to vanish so the
Joule heat cannot be conserved by an increase in temperature.
Instead, conservation proceeds by the QED induced creation of
QED photons inside the film, the QED photons creating charge
Q by Einstein’s photoelectric effect.
QED = Quantum Electrodynamics
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Memristor Geometry
D
+
QED
Radiation
D
t
t
d
d
-
t
+
QED
Radiation
L
-
t
I
I
Thin Film
I
Nanowire
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Proposal
The charge in nanoelectronic circuit elements is a QM effect
caused by photolysis from QED radiation created from the
conservation of Joule heat that otherwise is conserved by
an increase in temperature.
At the nanoscale, QM creates charge
instead of the classical increase in temperature
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Heat Capacity of the Atom
Classical Physics (kT > 0)
QM
(kT = 0)
hc

E
  hc  
exp  kT   1
 
 
kT
0.0258 eV
Nanostructures
In nanostructures, QM requires atoms to have zero heat capacity
ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
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Conservation of Energy
Lack of heat capacity by QM precludes Joule heat
conservation in memristors by an increase in
temperature, but how does conservation proceed?
Conservation Proposal
Generally, absorbed EM energy is conserved by creating QED
photons inside the nanostructure - by frequency up or down conversion to the TIR resonance of the nanostructure.
TIR = Total Internal Reflection
Up-conversion produces high energy QED photons in memristors,
but down-conversion also occurs, e.g., redshift of galaxy light in
dust in the 2011 Nobel in physics on an expanding Universe
ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
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TIR Confinement
Since the refractive index of the memristor is greater than that
of the surroundings, the QED photons are confined by TIR
(Tyndall 1870)
Memristors ( films, wires) have high surface to volume ratio,
but why important?
Propose EM energy absorbed in the surface of memristors
provides the TIR confinement of the QED photons.
Since the QED photons have wave functions that vanish normal
to the surface, QED photons are spontaneously created by
Joule heat dissipated in memristors
f = c/
 = 2nd (or 2nD)
E = hf
ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
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QED Heat Transfer
QQED is non-thermal radiation at TIR frequency
QED
Photons
Currently, K < Bulk in thin films is explained by
scattering of phonons, but if QQED is included in
heat balance, then K = Bulk
Phonons
QED Radiation
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
QED Photons and Excitons
QED Photon Rate
P = Joule heat
E = QED Photon energy
 = Absorbed Fraction
Exciton Rate
Y = Yield of Excitons / QED Photon
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Exciton Response
Electrons
Holes
Where, QE and QH are number electrons and holes, F is the field, and
E and H are electron and hole mobility
Taking F = Vo sin t / d,
Solution by Integrating factor gives
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Resistance and Current
 = Conductivity  = Resistivity
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Simulation
R
I
d = 50 nm , f = 5 kHz, and Vo = 1 V
Ro = 100  and P = 10 mW
H = 2x10-6 cm2/V-s
ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
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Hysteresis Curve
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30,
Conclusions
Modern day electronics was developed for the
macroscale, but a QM approach is suggested at the
nanoscale where memristive effects are observed.
Memristive effects in PCRAM films by melting are
negated by QM. Ovshinsky’s redistribution of charge
carriers by QM is more likely.
Memristors have nothing to do with the notion of the
missing fourth element necessary for completeness.
Memristor behavior is simply a QM size effect.
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Expanding Unverse
In 1929, Hubble measured the redshift of galaxy light that
by the Doppler Effect showed the Universe is expanding.
But cosmic dust of submicron NPs permeate space and
redshift galaxy light without Universe expansion
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Redshift in Cosmic Dust
Based on classical physics, astronomers assume absorbed
galaxy photon increases temperature of dust NPs
Galaxy
Photon

Dust
o = 2nD > 
Redshift
Photon
o
Redshift without Universe expansion
ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
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Nobel Mistake
Astronomers Schmidt, Pearlmutter, and Reiss got the 2011
Nobel in Physics for an accelerated expanding Universe
Referring to his calculation showing acccelerated Universe
expansion, Reiss is quoted as saying:
"I remember thinking, I've made a terrible mistake and I have
to find this mistake"
Others said: “[Riess] did a lot after the initial result to show
that there was no sneaky effect due to dust absorption“
Reiss did make a mistake - Redshift does occur in dust
No Universe expansion, accelerated or otherwise
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011
Questions & Papers
Email: [email protected]
http://www.nanoqed.org
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ICMON 2011 : Inter.l Conf. Micro, Opto, Nanoelectronics, Venice, Nov. 28-30, 2011