Electron-Phonon Coupling in Charge Density Wave ZrTe 3. Moritz Hoesch , Alexey Bosak, Alessandro Mirone, Michael Krisch European Synchrotron Radiation Facility ESRF Helmuth Berger École Polytechnique Fédérale de Lausanne, Suisse Dmitry Chernyshov Swiss-Norwegian Beamlines at ESRF. - PowerPoint PPT Presentation
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Slide: 1ECRYS 2008 – Cargèse 25. 8. 2008
Electron-Phonon Coupling in Charge Density Wave ZrTe
3
Moritz Hoesch,
Alexey Bosak, Alessandro Mirone, Michael KrischEuropean Synchrotron Radiation Facility ESRF
Helmuth Berger École Polytechnique Fédérale de Lausanne, SuisseDmitry Chernyshov Swiss-Norwegian Beamlines at ESRF
Slide: 2ECRYS 2008 – Cargèse 25. 8. 2008
ZrTe3 crystal structure and resistivity
prismatic (ZrTe3)∞ chains along b
Te – Te chains along aS. Takahashi et al. Journal de Physique 6 (1983) C3-1733
D.J. Eaglesham et al. J.Phys. C 17 (1984) L697
resistivity anomaly along a and c
anisotropy
a b
c a
CDW
0 1 2 mm
TCDW = 63 K, QCDW = (1/14 0 1/3 )
Slide: 3ECRYS 2008 – Cargèse 25. 8. 2008
anomalous feature in the diffuse scatteringdiffuse scattering at SNBL BM01A reconstructed a*-c* plane MAR345 image plate detector
(h0l)-plane (h0l)-plane
T = 295 K(4.7 TCDW)
T = 80 K(1.3 TCDW)
qCDW = (0.07 0 0.3333)
a*c*
(300) (400)
(301) (401)
Slide: 4ECRYS 2008 – Cargèse 25. 8. 2008
dispersion across qCDW
qCDW
to(4 0 1)
6
5
4
3
2
1
0
energy (meV)
-4.00-3.96-3.92-3.88along qCDW (a* component)
dispersion at T = 100 K sinusoidal model
qCDW
Slide: 5ECRYS 2008 – Cargèse 25. 8. 2008
temperature evolution of the Kohn anomaly
giant Kohn anomaly leads to the lattice instability.
2/1
014.1ln ⎟⎟
⎠
⎞⎜⎜⎝
⎛ −⋅≅⎟⎟
⎠
⎞⎜⎜⎝
⎛⋅−=
CDW
CDW
BniCDW T
TTb
Tka
εωω
mean field theory
observation close to
8/1
⎟⎟⎠
⎞⎜⎜⎝
⎛ −∝
CDW
CDWCDW T
TTω
5
4
3
2
1
0
energy (meV)
-4.00-3.96-3.92-3.88along qCDW (a* component)
T = 292 K T = 158 K T = 100 K T = 83 K T = 78 K T = 73 K T = 68 K model
3.0
2.5
2.0
1.5
1.0
0.5
0.0
phonon frequency (meV)
43210(T - Tc) / Tc
ωni
phonon frequency atqCDW
(( -T Tc)/Tc)(/8)
(( -T Tc)/Tc)(/2)
Slide: 6ECRYS 2008 – Cargèse 25. 8. 2008
origin of the diffuse scattering intensity
IXS intensities from fit vs diffuse scattering intensity
diffuse scattering is dominated by non-phonon scattering--> onset of order contributes strongly to diffuse scattering