Todays program
(1) Further breakdown / digestion of the Peierls Transition
(2) Overview of charge order in one and two/dimensional materials
Weekly overview
Today 25.09 Peiels Transitions & charge ordering Tomorrow 26.09 Kramers-Kronig relations
Monday 02.10 Quantum Oscillations
Tuesday 03.10 Angle-resolved photoemission spectroscopy
Tasks
Today 25.09 Peierls Transitions & charge ordering Tomorrow 26.09
Tasks: Kramers-Kronig (KK) relations
Read: Kittel, Chapter: “Optical Processes & Excitons”
Until ”Excitons” section.
Read: Note 1 and 2 about KK - relations Monday 02.10
Tasks: Quantum Oscillations
Read: Kittel, Chapter: “Fermi Surfaces (FS) and Metals”
Section: “Experimental Methods in FS Studies”
Hand-in exercise sheet Tuesday 03.10
Tasks: Angle-resolved photoemission spectroscopy
Bechgaard Salts
beta-co-(BEDT-TTF)2I3
CRYSTAL STRUCTURE
J. Phys.: Condens. Matter 25 (2013) 343201
Bechgaard Salts
RESISTIVITY
J. Phys.: Condens. Matter 25 (2013) 343201
Bechgaard Salts
TWO-DIMENSIONAL SYSTEMS
Dichalcogenides: X
Examples
MoS2 NbSe2 IrTe2
..
....
Niobium –diselenide:
NbSe
2Niobium –diselenide:
NbSe
2TaS e
2Nature Materials 7, 960 (2008)
IrTe
2Nature Communications 6, 7342 (2015)
TaSe
2Phys. Rev. Lett. 100, 196402 (2008)
NbSe
2Oxides
La2-xSrxNiO4 La2-xSrxCoO4 La2-xSrxCuO4
Nature Communications 7, 11632 (2016)
Different types of charge order
Charge stripe order
Checkerboard order
Nature Communications 7, 11632 (2016)
Different types of charge order
E. Fradkin & S. A. Kivelson
Nat. Phys. 8, 864 (2012) https://www.bnl.gov/newsroom/news.php?a=1865
John Tranquada et al., Nature 375, 561 (1995)
La2-xBaxCuO4
Cuprates: Stripe order
Proposal: literature presentation
Topic: Charge order in the high-temperature superconductor YBa2Cu3O7-x
Science 337, 821–825 (2012)
Nature Physics 8, 871-876 (2012) Science 350, 949–952 (2015)
Nature Communications 7, 11494 (2016)
Presentation date: 03.10.12 or 10.10.12
