setup - w2agz aps march san...ground state energies via gibbs2: cuse & cute min gse at a0 = 5.0...
TRANSCRIPT
![Page 1: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/1.jpg)
Setup
![Page 2: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/2.jpg)
A DFT Study of Electron-Phonon Coupling in
Proxy CuX (X = S, Se, Te) Structures and Its Relationship
to Possible Manifestation of Superconductivity
Paul M. Grant W2AGZ Technologies
Robert H. Hammond
Stanford University
Session Q11 Chalcogenide Superconductors
2:30 PM – 4:54 PM, Wednesday, 4 March
Paper 11 4:06 PM – 4:18 PM
Room 007B
![Page 3: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/3.jpg)
– Our Computational Tool Box –
• DFT + Hubbard U
– Quantum Espresso
• Fermiologies, States (DOS), Phonons, e-p “Lambda”
• Graphics
– Xcrysden, XMGRACE
• Fermi Surfaces, Projected DOS
• Modeling
– Debye Temperatures a la Gibbs2 Package
• Thanks to Alberto Otero-de-la-Rosa, http://azufre.quimica.uniovi.es/src/gibbs2/gibbs2.pdf
– Then Superconductivity via Eliashberg/McMillan!
![Page 4: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/4.jpg)
“Configuration/Coordination Space”
Relative Ground
State Energies
Tennorite
The Various Flavors of Copper “Monoxide”
“1-2-3”
tet-rs-CuO
• Siemons, et al. (2009) • Grant (2008) • Franchini Group (2011) • Cococcioni Group (2011)
Can we compute/synthesize the S, Se, Te analogues ...and what would be their physical properties wrt magnetism and superconductivity?
Magnetic properties revealed at APS MM Denver 2014. Now superconductivity!
![Page 5: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/5.jpg)
CuO
Ground State Energies via Gibbs2: CuO & CuS
CuS
Min GSE at a0 = 4.13 Å
(Cubic)
Cubic
CuO (Cubic)
D = 693 K
Min GSE at a0 = 3.9 Å, c/a = 1.15
Tetragonal
CuO (Tet)
D = 733 K
Min GSE at a0 = 4.75 Å
CuS (Cubic)
D = 525 K
Min GSE at a0 = 4.5 Å, c/a = 1.12
CuS(Tet)
D = 780 K
![Page 6: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/6.jpg)
CuSe
CuTe
Ground State Energies via Gibbs2: CuSe & CuTe
Min GSE at a0 = 5.0 Å
Cubic
CuSe (Cubic)
D = 409 K
Min GSE at a0 = 5.34 Å
CuTe (Cubic)
D = 327 K
Min GSE at a0 = 4.75 Å, c/a = 1.1
Tetragonal
CuTe (Tet)
D = 622 K
Min GSE at a0 = 5.05 Å, c/a = 1.1
CuTe (Tet)
D = 489 K
![Page 7: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/7.jpg)
Superconductivity and Phonons BCS via Eliashberg-McMillan
† †
, , ,
, ,
( )mn m n
el phH g c c b b
q
k q k k q k q q
k q
,2
2
, , , ,
,
1( ) ( ) ( ) ( )
( )
mn
m F n F
mnF
F gN
q
q k q k k q k
q k
,2
, , , ,
,
2( ) ( )
( )
mn
m F n F
mnF
gN
q
q k q k k q k
kq
2
,0
,
( )2
Fd
q
q
To get , need to compute ,mng
q
k q k!
NB! The “double deltas” will be approximated by two Gaussians
of width “sigma ()” whose numerical convergence is
governed by imposed precision limits and basis set symmetry.
Con Quidado!
![Page 8: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/8.jpg)
Eliashberg-McMillan-Allen-Dynes
, ,
, , ,,
/ 4mn
m KS nh Vg
q
q
q k q kk q k
, ,
,
i
KSKS s
s s
V eV u
u N
q R
q q
R R
D
*
1.04 1exp
1.45 1 0.62CT
Let’s Go!
![Page 9: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/9.jpg)
CuSe TC
D = 409 K; * = 0.0
Cubic
TC(max) ~ 17 K
Tetragonal
TC(max) ~ 36 K
D = 623 K; * = 0.0
![Page 10: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/10.jpg)
CuTe TC
D = 327 K; * = 0.0
Cubic
TC(max) ~ 4.2 K
Tetragonal
TC(max) ~ 45 K
D = 490 K; * = 0.0
![Page 11: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/11.jpg)
CuS TC
D = 525 K; * = 0.0
Cubic
TC(max) ~ 28 K
Tetragonal
D = 780 K; * = 0.0
Whoops! • Unphysically “negative” ! • Convergence issues? • Symmetry issues? • “Needs more work ;-)”
![Page 12: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/12.jpg)
OK...Now What About CuO? Well?
Assume a doping density for“g = 0.15 holes/CuO”
in this region for experimentally
determined Tet-CuO that effectively screens “U” such that we have an “ideal” Fermi liquid.
Then what does Gibbs2 and Eliashberg-McMillan tell us about the possibility of electron-phonon mediated superconducting copper oxide perovskites?
![Page 13: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/13.jpg)
CuO (tetragonal)
q = 0.15/CuO TC
D = 928 K
TC(avg) ~ 75 K
* = 0.05
with maybe a little help from
their spins!
Ipso Facto... At least at optimum
doping...
the holes are paired by lattice
shakes...
![Page 14: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/14.jpg)
So What Else is New? Macfarlane, Rosen, Seki, SSC 63, 831 (1987)
Raman Spectroscopy of YBCO
We can see Phonons have been there
ever since the Creation!
![Page 15: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/15.jpg)
At the End of the Day... Can We Actually Make Any of this Stuff?
![Page 16: Setup - W2AGZ APS March San...Ground State Energies via Gibbs2: CuSe & CuTe Min GSE at a0 = 5.0 Å Cubic CuSe (Cubic) D = 409 K Min GSE at a0 = 5.34 Å CuTe (Cubic) D = 327 K Min GSE](https://reader036.vdocuments.mx/reader036/viewer/2022071412/610830ca7fe099055960d7ab/html5/thumbnails/16.jpg)
Aluminum (Quantum-ESPESSO Example)
* = 0.1 Log_w ~ D
TC(exp) = 1.2 K