Chemistry Reference
In-Depth Information
Z
0.0
a
b
c
-0.5
d
d'
-1.0
0.0
0.5
1.0
momentum along b* (Å
-1
)
Figure 6.12. Grey-scale plot of the ARUPS in comparison to the band disper-
sion obtained by DFT calculations. Reprinted with permission from M. Sing,
U. Schwingenschlolgl, R. Claessen, P. Blaha, J. M. P. Carmelo, L. M. Martelo,
P. D. Sacramento, M. Dressel and C. S. Jacobsen,
Physical Review B
,
68
, 125111
(2003). Copyright (2003) by the American Physical Society.
should perhaps be saved from oblivion and synthesized again in order to perform
ARUPS measurements.
High-resolution UPS experiments performed on (TMTSF)
2
PF
6
and
(TMTSF)
2
ClO
4
single crystals confirm the absence of intensity at
E
F
(Vescoli
et al.
, 2000). The surfaces of BFS are extremely sensitive to VUV irradiation,
so that photoemission data published for such materials have to be cautiously
examined. A fit of the leading edge of the spectra close to
E
F
to the Luttinger
liquid power-law expression
|
E
−
E
F
|
υ
leads to
K
ρ
∼
2, corresponding to the
very strong repulsion limit. This is confirmed by measurements of the optical
conductivity
0
.
) of the three Bechgaard salts (TMTSF)
2
PF
6
, (TMTSF)
2
AsF
6
and
(TMTSF)
2
ClO
4
, where
K
ρ
σ
(
ω
23 is derived (Schwartz
et al.
, 1998). In this case
consistent deviations from the simple Drude response are found, with
0
.
) instead
consisting of two distinct features: a narrow mode at low energy containing a very
small part of the spectral weight (
σ
(
ω
∼
1%), and a high-energy mode centred around
