Title: Electron-Phonon Interaction in the Polymeric Superconductor, Polysulfur Nitride, (SN)x
1Electron-Phonon Interaction in the Polymeric
Superconductor, Polysulfur Nitride, (SN)x
- Paul M. Grant
- IBM Research Staff Member, Emeritus
- Session P8 Focus Session Novel Superconductors
Miscellaneous Materials - 2007 APS March Meeting
- Talk P8.00007, 1239 PM 1251 PM
- Wednesday, 7 March, CCC Korbel 1C
- Denver, Colorado
http//www.w2agz.com/snxaps07.htm
21975 Superconductivity Discovered at 300 degrees
in Polysulfurnitride, (SN)x
3Precursor to a Nobel Prize
4Thanks, Grazie, Hvala Lepa to
- Paolo Giannozzi and his team at
CNR-INFM-Democritos for developing and supporting
PWscf and Quantum-Espresso - Anton Kokalj of the Jozef Stefan Institute,
Slovenia, for PWgui and XCrySDen - The UK Cambridge crystal structure data base team
for developing and support of the Mercury crystal
imaging package
and all this for free! A paradigm for a future
world order?
5Structure of (SN)xCohen, et al., JACS 98, 3844
(1976)
- Monoclinic P21/c
- a4.485, b3.767, c8.452, ?106.43
- 4 N, 4 S, 2 chains
- S32.06, N14.007
- SNe3s23p4, NHe2s22p3
- 44 electrons
- 22 bands
- Many phonon IRs (12-24)
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7b-axis unique
8b-axis unique(but same notation for c-axis)
Z
E
?
U
?
A
9Band Structure of (SN)x
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14Electron-Phonon Coupling
15Wierzbowska, et al., arKiv.cond-mat/0504077
16Experimental Apparatus
- Linux box running SUSE 10.1
- Dual Xeon (1.2 GHz) Motherboard, 2 GB RAM, 133
MHz FSB, Vintage ca. 2003 - Democritos Quantum Espresso Package
- Vanderbilt US pseudopotentials for N S
- pw.x, 4x4x4 MP grid
- ph.x, tr2_ph 1e-11 ddv_scf2
- 1 q-point gt 25 hours wall time
- Still not a fully converged calculation!
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21To-Do List
- Get access to some more flops (BlueGene?)
- Compute nesting vectors
- Compute Eliashberg and compare with Binnig
tunneling - Compute full lambda
- Dope (e.g., Br ?)