micky holcomb condensed matter physicist west virginia university

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Micky Holcomb Condensed Matter Physicist West Virginia University [email protected] The Physics of Faster, More Energy-Efficient Computers http://community.wvu.edu/~mbh039/

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The Physics of Faster, More Energy-Efficient Computers. Micky Holcomb Condensed Matter Physicist West Virginia University. http://community.wvu.edu/~mbh039/. [email protected]. Who cares about Physics?. Why would one study Physics?. The Physics of Cell Phones. Power Switch. - PowerPoint PPT Presentation

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Page 1: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Micky HolcombCondensed Matter Physicist

West Virginia University

[email protected]

The Physics of Faster, More Energy-Efficient Computers

http://community.wvu.edu/~mbh039/

Page 2: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Who cares about Physics?

Why would one study Physics?

Page 3: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

The Physics of Cell Phones

Physics is responsible for the components in your

phones and computers.

The internet (formally the NSFnet*) is due to basic science funding.

Memory

Battery Connector

Audio & Charging

SIM Card

Finding Signal

Power Switch

Camera

Backup Battery

GPS & WiFiPower

Amplifier Runs the Screen

Connection to Other Devices

Keeps Time

*http://en.wikipedia.org/wiki/NSFNET

Page 4: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Physics Helps Makes Life Better

We learn about the basic products of nature and learn how to make some beefy devices.

Page 5: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Computers Have Progressed

Page 6: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Physics Makes Faster Computers

Page 7: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

What is Electricity?

In some materials, these electrons move freely

under an applied voltage.

Page 8: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

What is a Transistor?

http://www.youtube.com/watch?v=CkX8SkTgB0g

ResistorTransformative

Changing Variable Resistor

Time

Page 9: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Improving Transistors

The number of transistors placed inexpensively on a

computer chip has doubled every ~2 years

(Moore’s Law)

This trend has allowed massive

progress in technology

Page 10: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Silicon

A voltage on the gate electrode can induce flow of electricity between the two other contacts called the source and drain.

The flow of electricity is affected by: the dielectric constant of the oxide,

the area of capacitor and the oxide thickness

1) Making Them Smaller

Area Speed

Area Electron flow

Thickness Electron flow

Page 11: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Quantum Tunneling?!?

Electrons are lazy!

If the hill isn’t too wide, they tunnel through it. Not good.

Page 12: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

• High dielectric constant• Low leakage current

• Works well with current Si technology

Many materials have been tried but none are as cheap and easy to manipulate as

existing SiO2.

2) Replacement Oxides

Page 13: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

3) StrainIndustry found that it could improve

electron travel in MOSFETs by straining (essentially squeezing) silicon.

Strain can allow quicker, more efficient transfer of

electrons.Strain can also affect other

properties of a material.

Page 14: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Ex: roads, airplane wings, medical inserts, building materials

Why We Care About Strain

Page 15: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Reaching the Limits

We are reaching the limit that these strategies can continue to

improve technology.

1) Scaling2) Replacements

3) Strain

Page 16: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Magnetic moment

electrons

4) Different Approach: Magnetism

Page 17: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

0 0 1

Problems with Magnetic FieldsRequire a lot of power

Heating problemsDifficult to localize – limits

size

Magnetic field

Using Magnetism

Page 18: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Ferroelectric

Multiferroic

Ferromagnetic

4) Different Approaches

Spontaneous magnetization whose direction can be

changed with an applied magnetic field

Spontaneous polarization whose direction can be

changed with an applied electric field (voltage)

Page 19: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

P1+

BiFeO

P1-

180°

P4-

109°P3-

71°

Using an electric field to change

magnetismMagnetic plane is perpendicular to the polarization

direction.

Electrical Control of Magnetism?Only room temperature

magnetic ferroelectric (BFO)

Page 20: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Physics at its Boundaries

Boundary- Simple idea: Grow a magnetic material on top of a ferroelectric

- BFO is not a good candidate

- Problem: the physics at boundaries is not yet well

understood

Page 21: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Magnetoelectric InterfaceLaser Molecular Beam Epitaxy(Laser MBE) A – Magnetic layer (LSMO)

B – Ferroelectric layer (PZT)C – Substrate

Programmable shutterChu YH, et. al., Materials Today 10 (10), 16 (2007)

SrTiO3

PbZrTiO3

LaSrMnO3

Page 22: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Visualizing the Nano

1 inch = 2.5 cm= 25 million nanometers (nm)

Nanometer objects are too small to see with our eyes.

We study structures that are only several nanometers in length.

Scientists must use powerful microscopes to image objects this small.

Penny = 0.06 inches thick (or 1,550,000 nanometers)

Human hair = 100,000 nm wide

Page 23: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Our “Laser”

Power of a laser pen:5 mW

Power of our lab’s laser:1500 mW

Paper will burn at 95 mW

Femtosecond pulses, one million times smaller than nanoseconds!

Page 24: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Cooling Down the PhysicsAntarctica reaches temperatures of

-129°F

Capable of reaching temperatures of -450°F

This is just above ABSOLUTE ZERO, the coldest possible temperature.

Cryostat

Other cool features:Low vibration stage

Sample rotation

Page 25: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Measurements Elsewhere

Experiments At National Labs: X-ray Dichroism

Photoemission Electron Microscopy (PEEM)

Page 26: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Beam of electrons forced by magnets to go around

in circles

X-rayselectrons

Sample

Collector

X-rays excite electrons which

tell us about many properties of the

material

electrons

150 Feet

X-ray Production

Page 27: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

As grown First E switch Second E switch

Electric Control of FM

Page 28: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

FerroelectricMagnetic

Multiferroic materials offer a pathway to new properties/devices.

As computers continue to get smaller, the physics becomes more interesting.

Basic physics research has allowed significant progress in computing and other modern day technologies.

Magnetic and ferroelectric materials can be imaged and studied at WVU and national laboratories.

Magnetic domains can be changed by an electric field.

Summary

Page 29: Micky  Holcomb Condensed Matter Physicist West  Virginia  University

Our Science Superheroes

Left to Right: Srinivas Polisetty (post-doc), Disheng Chen (grad), Jinling Zhou (grad), Evan

Wolfe (undergrad), Micky Holcomb (advisor) and Charles Frye (undergrad) National Chiao Tung University (Taiwan)

A few of my collaborators: