1. Opening… 1 1

2. Paul M. Grant IBM Research Staff Member, Emeritus
A DFT (LDA+U) Study of the Electronic Properties of Layered, Square-Planar Coordinated Copper Monoxide Structures -- Proxies for High Temperature Superconductivity --
Paul M. Grant IBM Research Staff Member, Emeritus
Financial Support From:
IBM Retiree Pension Fund Prior to 1990
Aging IBM Pensioner 2 2 2

3. Prelude “Electronic Properties of Rocksalt Copper Monoxide,”
APS MAR , P. M. Grant, Pittsburgh (2009)

4. Tools QUANTUM-ESPRESSO Suit of Codes “Dial-in” Parameters Hardware
DFT (LDA+U) plus electron-phonon
Graphics by Tone Kolalj (XCrysDen)
“Dial-in” Parameters
G2 = 40 Ry ρ = 320 Ry
Convergence ≤ 10-6 Ry
“Smearing” = Methfessel-Paxton
Psuedopotentials: Ultrasoft, XC = Perdew-Zunger Cu: 3d94s2 O: 2s22p4
Hardware
3.33 GHz Intel Core i7 – 12 GB+

5. Findings
Basic Asymmetric af-CuO Cell
Spin Up

6. Are There Phonons w/ High-Tc in YBCO?
Fig. 38: Pintschovius and Reichardt, in Furrer, ISBN

7. Harashima, et al., Physica C263, 257 (1996)
Yes -- They’re There!
Harashima, et al., Physica C263, 257 (1996)
Pyka, et al., PRL 70, 1457, (1993)

8. Macfarlane, Rosen, Seki, SSC 63, 831 (1987)
Raman Spectroscopy of YBCO

10. Cubic Rocksalt Copper Monoxide
a = b = c = Å 10

11. Rocksalt CuO Combined DOS
N(E) (states/eV)
EF = eV eV

12. Rocksalt CuO BZ X M Γ X X

13. Rocksalt CuO Bands
Note Degeneracies! eV EF Γ X M X Γ X X 13

14. Rocksalt CuO Band Widths
Note Degeneracies! 14

15. Rocksalt CuO Fermiology5 8 12 10 15

16. Rocksalt CuO Fermiology (Combined)
Note (Near) Degeneracies!
Jahn-Teller Unstable?
Alex M? 16

17. Non-Magnetic Cubic Rocksalt CuO -- Electron-Phonon Properties --
α2F(ω)
λ ~ 0.6 – 0.7
Other sc’s…
TC (K) λ μ*
K3C60
16.3
0.51 -
Rb3C6 0
30.5
0.61
Cs3C6 0
47.4
0.72
σ = 0.04 17 17

18. Square-Planar Copper Monoxide “Film”
a = b = Å
c = 6 x = Å 18

19. “Thin Film” Rocksalt CuO Combined DOS
N(E) (states/eV)
EF = eV eV

20. “Thin Film” CuO BZ X M Z Γ X

21. “Thin Film” CuO Bands
Note Degeneracies! eV EF Γ X M X Γ Z X 21

22. “Thin Film” CuO Band Widths
Note Band Offsets! 22

23. “Thin Film” CuO Fermiology (Combined)
2kF
“Nesting Fermi Lines”
→ CDW? → SDW? → HTSC?
 ~ ? 23

24. “Rocks” “Films”

25. “Rocks” “Films”

26. “Rocks” “Films”

27. “Rocks” “Films”
“Jahn – Teller” “Nesting”

28. af-CuO c=6*a U~0.001 eV

29. af-CuO c=6*a U~0.001 eV

30. af-CuO c=6*a U~0.001 eV

31. 3D phase diagram of overdoped La2-xCexCuO4 with 0.15 ≤ x ≤ 0.19.
Shakes & Spins
Copacetic, Competitive or Conundrum?
That is the question…anon
3D phase diagram of overdoped La2-xCexCuO4 with 0.15 ≤ x ≤ 0.19.
Bottom Line:
Can studying CuO proxies with DFT
+ LDA+U
+ phonons
provide the answer?
I say “Yes,” but…
How to compute λ(SDW)?
Size Matters…
…and I need a… BIGGER COMPUTER!
Pairing associated with quantum critical energy scales in superconducting electron-doped cuprates
K. Jin, N. P. Butch, K. Kirshenbaum, J. Paglione, and R. L. Greene*
-submitted to Nature-
*will answer all questions…