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Whither Superconductivity?

Whither Superconductivity?

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Whither Superconductivity?. Superconductivity The Day Before Yesterday – Yesterday – Today - Tomorrow. Karl Alexander Mueller. Vitaly Lazarevich Ginzburg. “Best wishes, and hang in there, Guys !”. Theory & Modeling. Bob Laughlin’s “Theory of Everything” (that matters). - PowerPoint PPT Presentation

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Page 1: Whither Superconductivity?

Whither Superconductivity?

Page 3: Whither Superconductivity?

Theory & Modeling

Page 4: Whither Superconductivity?

Bob Laughlin’s “Theory of Everything” (that matters)

Where’s spin, Pauli and Darwin? Ya screwed up, Bob…should’a used the

many body Dirac equation!Oh yeah, and maybe

Maxwell, Boltzman and Gibbs, too…and Newton’s

Apple.

The crunch comes when I with i >= 3 -> “thermodynamic limit.”

“Size Matters !”

Page 5: Whither Superconductivity?

1

*CT a e

“Naked BCS”

Where

Tc = Critical Temperature

= Boson Characteristic Temperature

= Fermion-Boson Coupling Constant

* = Fermion-Fermion Repulsion

a = “Gap Parameter, ~ 1-3”

Fk E

Page 6: Whither Superconductivity?

“Put-on !”

Mike Norman, Alexandria, VA 2006

Page 7: Whither Superconductivity?

Really High-Tc

~109 K

Page 8: Whither Superconductivity?

Electron-Phonon Coupling a la Migdal-Eliashberg-McMillan

(plus Allen & Dynes)

First compute this via DFT…

Then this…

Quantum-Espresso (Democritos-ISSA-CNR)

http://www.pwscf.org Grazie!

Page 9: Whither Superconductivity?

Electrons

Holes

Polysulfur Nitride: The World’s First 330 Degree Superconductor !

Legal Disclaimer: The Temperature Units are Millikelvin.

Page 10: Whither Superconductivity?

So…

• Now we can compute the sc phase diagram of Al, Nb, MgB2, etc., as accurately as can be measured.

• Then has phonon-mediated superconductivity in s-p (light elements…some not so light) systems become “solved science?”

• Maybe…ask Warren Pickett.• Unresolved: ultra-strong and flux

dynamics.

Page 11: Whither Superconductivity?

What to do next?

• Develop DFT algorithms to compute “exotic” pairing mechanisms, analogous to e-p.

• Especially polarization (“exciton”) and magnetic (“all flavors,” particularly “negative-U”).

• Marvin ?

Page 12: Whither Superconductivity?

Materials & Methods

Page 13: Whither Superconductivity?

Guidance from Our Elders• “Don’t listen to theoreticians” (B. Matthias, ca.

1970s).• “To make a long story short, searches for high-

temperature superconductors, especially with the existing obscurities in the area of theory, may lead to unexpected results and discoveries” (V. L. Ginzburg, 1984).

• “At the extreme forefront of research in superconductivity is the empirical search for new materials” (M. R. Beasley (1983), as communicated by K. A. Mueller and J. G. Bednorz, (1986)).

• “If you find an old metal laying around in the literature, try cooling it down,” (P. M. Grant, 1976).

Page 14: Whither Superconductivity?

Exactly What is a“Superconductor?”

• Does it have to be a “perfect conductor?”– i.e., zero TAFF

• Does it have to exclude flux (Meissner)?• Or does it only need to be a “real good

conductor (“ultraconductor”)?”– 200x Cu @ 300 K @ 1000 Hz

• Ballistic CNTs• Sliding P-F CDWs• Charged Solitons• ???

Page 15: Whither Superconductivity?

Materials Pathways

• Light Elements• Heavy Elements• Many Elements• All Elements

• COMBINATORIAL !

Page 16: Whither Superconductivity?

Heat ‘em ‘n’ Beat ‘em

Get Wet

Superconductor Sandwiches “Togo”

Squeeze Play

Fabrication

Page 17: Whither Superconductivity?

NanoMachining

Page 18: Whither Superconductivity?

““Magic Carpet”Magic Carpet”

Page 19: Whither Superconductivity?

Applications

Page 20: Whither Superconductivity?

Low-Tc Today

Quantum Computin

g

Page 21: Whither Superconductivity?

Electronics

“A room temperature device !”

Page 22: Whither Superconductivity?

WireOxide Powder

1.PowderPreparation

A. ExtrusionB. Wire Draw

C. RollingDeformation& Processing

3.

Oxidation -Heat Treat

4.

Billet Packing& Sealing

2.

Gen 1

Gen 2Oxide Powder1.Powder

Preparation

A. ExtrusionB. Wire Draw

C. RollingDeformation& Processing

3.

Oxidation -Heat Treat

4.

Billet Packing& Sealing

2.

Oxide Powder1.Powder

Preparation

A. ExtrusionB. Wire Draw

C. RollingDeformation& Processing

3.

Oxidation -Heat TreatOxidation -Heat Treat

4.

Billet Packing& Sealing

2.

Gen 1

Gen 2

Major Players: US, Japan, China

Page 23: Whither Superconductivity?

Wire Performance

Page 24: Whither Superconductivity?

Rotating MachineryCourtesy AMSC

Major Players:

• AMSC

• SEI

Page 25: Whither Superconductivity?

Cables

Page 26: Whither Superconductivity?
Page 27: Whither Superconductivity?

“You can’t always get what you want…”

Page 28: Whither Superconductivity?

“…you get what you need!”

Page 29: Whither Superconductivity?

Where there is no vision,the people perish… Proverbs 29:18