an introduction to the optical spectroscopy of solidsctcp/china_us_workshop/nanlin...an introduction...
TRANSCRIPT
![Page 1: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/1.jpg)
An introduction to the optical
spectroscopy of solids
Nan Lin Wang
Institute of Physics
Chinese Academy of Sciences
![Page 2: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/2.jpg)
Outline
1. Optical constants and their relations
(Optical constants, Kramers-Kronig
transformation, intra- and interband transitions)
2. Drude model of simple metal (example of
application)
3. Spectroscopy of correlated electrons
4. THz time domain spectroscopy (Particularly
optical pump, THz probe)
![Page 3: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/3.jpg)
References
• C. Kittle, Solid State Physics
• F. Wooten, Optical properties of solids (Academic Press,
1972)
• M. Dressel and G. Grüner, Electrodynamics of solids
(Cambridge University Press, 2002)
![Page 4: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/4.jpg)
Units:1 eV = 8065 cm-1 = 11400 K
1.24 eV=10000 cm-1
D. Basov, et al.
Rev. Mod. Phys.
(2011)
Optical spectroscopy is a primary tool to probe the charge
dynamics and quasiparticle excitations in a material.
I. Optical constants and their relations
![Page 5: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/5.jpg)
The electrodynamical properties of solids
described by a number of so-called “optical constants”:
complex refractive index, or complex dielectric constants,
or complex conductivity.
Those optical constants could be probed either directly
(ellipsometry, ultrfast laser-based time domain terahertz
spectroscopy,…) or indirectly (reflectance
measurement over broad frequencies).
![Page 6: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/6.jpg)
Optical constants
Consider an electromagnetic wave in a medium
index refractive :)n( ),c/n(/q vwhere
)(
0
)/(
0
)(
0
t
c
nxi
tvxitqxi
y eEeEeEE
If there exists absorption,
K: attenuation factor
)(
0
tc
nxi
c
Kx
y eeEE
c
Kx
y eEE2
2
0
2I
))(
(
0 t
c
xNi
y eEE
)()()( iKnN Introducing a complex refractive index:
x
y E
Intensity
![Page 7: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/7.jpg)
Reflectivity
If n, K are known, we
can get R, ; vice versa.
1
2
)1(
)1(|)(||/|
)1(
)1(
1
1
)(
22
22
2222
)(
22
22
)(
Kn
Ktg
Kn
KnrEER
eKn
Kn
iKn
iKn
errE
E
inref
i
i
in
ref
1/ 2
1/ 2
1/ 2
1
1 2 cos
2 sin
1 2 cos
Rn
R R
Rk
R R
![Page 8: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/8.jpg)
Dielectric function
)()(2)(
)()()(
))()(()()()(
)()(
)()0,(,0,
),(),(),(
2
22
1
2
21
Kn
Kn
iKni
N
qqphoton
qEqqD
0 /a~1Å-1
Infrared
q=2/~10-4 Å-1
1 2
1 2
2 2
1
2 2
1
1( ) ( ) ( )
2
1( ) ( ) ( )
2
n
k
or
![Page 9: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/9.jpg)
conductivity
In a solid, considering the contribution from ions
or from high energy electronic excitations
)(i41)( amics,electrodynBy
)()( 21
)(i4)(
![Page 10: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/10.jpg)
Now, we have several pairs of optical
constants:
n(), K()
R(), ()
1(), 2()
1(), 2()
Usually, only R() can be measured
experimentally.
![Page 11: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/11.jpg)
High- extrapolations:
R~ -p (p~0.5-1, for intermedate region)
R~ -n (n=4, above interband transition)
Low- extrapolations:
Insulator: R~ constant
Metal: Hagen-Rubens
Superconductor: two-fluids model
2 20
ln ( ')'
'
RP d
For optical reflectance
( ) ( )
ln ( ) (1/ 2) ln ( )
ir R e
r R i
Kramers-Kronig relation
-- the relation between the real and
imaginary parts of a response function.
21 2 2
0
' ( ')d '2( )
'P
12 2 2
0
( ')d '2( )
'P
![Page 12: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/12.jpg)
Reflectivity measurement
![Page 13: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/13.jpg)
FTIR
![Page 14: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/14.jpg)
C. C. Homes et al.
Applied Optics 32,2976(1993)
FT-IR spectrometer In situ evaporation
In-situ overcoating technique
![Page 15: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/15.jpg)
Δk
Δω
X
k,E e- k’,E
k,E
k’,E’
q,ωq e-
(a) Impurity-assisted absorption
(b) boson-assisted absorption
Holstein process, if phonons are involved.
Intraband transition
Eg h
Ec(k)
Ev(k)
Interband transition
| , , ( )
| , , ( )
v
c
v k E k
c k E k
( ) ( ) ( )c v cvE k E k E k
3( )
(2 ) | ( ) |k cv
V dsJ E
E k
2 22
2 2 2
8( ) ( ) | ( ) |vc
eJ p
m
Kubo-Greenwood formula
)(4
1)( 21
Infrared light cannot be absorbed
directly by electron-hole excitation.
![Page 16: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/16.jpg)
4( ) ( )
i
22
2
12
22
2
1
1
14
/1
p
p
R
1
p’
1/
1/ dc
-1
1()
(m*/m)Neff
energy
Im(-1/ )
'2
2 '2 2 2 2
'
/1Im{ }
( ) ( )
/
p
p
p p
2
1
0
( )8
pd
2
0 1( )
1 4 1/
D
i i
简单金属:Drude model
![Page 17: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/17.jpg)
举例:Parent compound 1T-TiSe2
• 1T-TiSe2 was one of the first CDW-bearing materials
• Broken symmetry at 200 K with a 2x2x2 superlattice
• Semiconductor or semimetal?
0 50 100 150 200 250 3000.0
0.5
1.0
1.5
2.0
2.5
3.0
mc
m
T (K)
Ti: 3d24s2
Se: 4s24p4
Ti : 3d band fully empty ?
Se: 4p band fully occupied?
related to the CDW mechanism
![Page 18: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/18.jpg)
Ti: 3d24s2
Se: 4s24p4
Ti : 3d band
Se: 4p band
![Page 19: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/19.jpg)
Excitonic Phases W. Kohn, PRL 67
The electron-hole coupling acts to mix the electron band and hole
band that are connected by a particular wave vector.
![Page 20: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/20.jpg)
0 100 200 300 400 500 6000.0
0.2
0.4
0.6
0.8
1.0
300K
225K
200K
150K
080K
050K
010K
Reflectivity
Frequency(cm-1)
TiSe2
0 1000 2000 3000 4000 50000.2
0.4
0.6
0.8
1.0
300K
225K
200K
150K
080K
050K
010K
Reflectivity
Frequency(cm-1)
TiSe2 single
crystal
G. Li et al., PRL (07a)
![Page 21: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/21.jpg)
0.15 eV
CDW gap Drude
Free carriers with very long
relaxation time exist in the
CDW gapped state FS is not fully gapped??
0 2000 4000 60000
1000
2000
3000
4000
300 K
225 K
200 K
150 K
80 K
50 K
10 K
1 (
S/c
m)
(cm-1)
0.4 eV
![Page 22: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/22.jpg)
100 1000 100000.2
0.4
0.6
0.8
1.0 300 K
10 K
dash curves: fit with Drude
+ two Lorentz
0 50 100 150 200 250 3000
2000
4000
6000
8000
0
200
400
600
800
1000
p (
cm
-1)
T (K)
1/
(cm
-1)
R
![Page 23: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/23.jpg)
Exciton-driven CDW
)(4 22
e
e
h
hp
m
n
m
ne
0 50 100 150 200 250 3000.0
0.5
1.0
1.5
2.0
2.5
3.0
mc
m
T (K)
G. Li et al., PRL (07a)
![Page 24: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/24.jpg)
0 10000 20000 30000 400000.0
0.2
0.4
0.6
0.8
1.0
R
(cm-1)
gold
0 5000 10000 15000 200000.0
0.2
0.4
0.6
0.8
1.0
R (cm
-1)
YBCO
Bi2212
Simple metal High-Tc cuprates
![Page 25: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/25.jpg)
Simple metal
Correlated metal
Electron correlations reflected in optical conductivity
Correlation effect:reducing
the kinetic energy of electrons,
or Drude spectral weight.
![Page 26: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/26.jpg)
Q M Si, Nature Physics 2009
![Page 27: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/27.jpg)
Basov and Chubakov, Nature Physics 2011
![Page 28: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/28.jpg)
Hubbard U physics:
DFMT
V2O3
![Page 29: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/29.jpg)
Sum rule
f-sum rule:
It has the explicit implication that at energies higher than the total
bandwidth of a solid, electrons behave as free particles.
Kubo partial
sum-rule:
The upper limit of the integration is much larger than the bandwidth
of a given band crossing the Fermi level but still smaller than the
energy of interband transitions. For , the Kubo sum
rule reduces to the f-sum rule.
WK depends on T and on the state of the system because of nk---
"violation of the conductivity sum rule", first studied by Hirsch.
kinetic energy
in the tight
binding model
In reality, there is no true violation: the change of the spectral weight of a given band would be
compensated by an appropriate change in the spectral weight in other bands, and the total
spectral weight over all bands is conserved.
![Page 30: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/30.jpg)
2
2
*2
*
1( , )
4 ( , )
1
4 1/ ( , ) [1 ( , )]
1
4 1/ ( , )
p
p
p
TM T i
T i T
T i
21
( )4 1
p
i
( , ) 1/ ( , ) ( , )M T T i T 1/,T: Frequency dependent scattering rate
: Mass enhancement m*=m(1+
Drude Model
Extended Drude Model
Let
e.g. Marginal Fermi Liquid model:
2 2
( , ) 1/ ( , ) ( , )
(0) ln2 c
M T T i T
xg N x i
Where x=max(||,T),
or x=(2+(T)2)1/2
2
2
1/ ( , ) ( / 4 )Re[1/ ( , )]
* / 1 ( ) ( / 4 ) Im[1/ ( , )]
p
p
T T
m m T
![Page 31: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/31.jpg)
The extended Drude model in terms of optical
self-energy
21
( , )4 ( ( , ) )
pT
T i
According to
Littlewood and
Varma, 1 2
( ) 2
2 [ ( ) ( )]
opi
i i
1 2
*
2 1
( ) 1/ ( ) 2
( ) (1 / ) 2m m
Optical self-energy
Relation to the 1/() and m*/m
![Page 32: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/32.jpg)
Hwang, Timusk, Gu,
Nature 427, 714 (2004)
Bi2212
![Page 33: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/33.jpg)
The electron-boson (phonon) interaction
T=0 K
P.B.Allen 1971 )()()(
2/1
0
2
Fd tr
0 1000 2000 30000
1200
2400
3600
4800
0.0
1.5
3.0
4.5
6.0
F
1
F
At 0K, based on Allen's formula
1c
m1
Wave number (cm-1)
_0=500 cm-1
=100 cm-1
_p^2=50000 cm-2
2 2
2
2 2 2 2 2
0
( )( )
pF
![Page 34: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/34.jpg)
S. V. Dordevic, et al. PRB 71, 104529 (2005)
22
2
20
2 41/ 1d F E
Allen’s formula for the scattering
rate in the superconducting state
E(x) is the second kind
elliptic integral
P.B.Allen 1971
![Page 35: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/35.jpg)
Optical spectra of a superconductor
T=0, London electrodynamics gives
)(41
or )(81
4/)(8
12221
0122
22
cd
ci
L
sn
L
psps
clean limit: <l 2>
Absorption starts at 2+.
dirty limit: >l 2<
Absorption starts at 2.
∵pippard coherence length
=vF/, =1/=vF/l
Ferrell-Glover-Tinkham sum-rule: missing area
is equal to the superconducting condensate. Clean limit dirty limit
![Page 36: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/36.jpg)
Coherent factors and characteristic spectral
structures in density wave or superconductors
![Page 37: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/37.jpg)
Gap feature in density waves
0 100 200 300 400 5000
3000
6000
9000
12000
20 K
300 K
70 K
20 K
15 K
8 K
1 (
-1cm
-1)
(cm-1)
300 K
200 K
100 K
70 K
50 K
dc values
URu2Si2
![Page 38: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/38.jpg)
Gap structure in superconductors
G. Li et al PRL 08
Cuprates, Homes data
Ba0.6K0.4Fe2As2
![Page 39: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/39.jpg)
Coherent peak below Tc
O.Klein et al PRB 94
T. Fischer et al PRB
2010 R. V. Arguilar et al,
arXiv:107.3677
铁基超导体的THz数据与NMR不同?S+-配对?
![Page 40: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/40.jpg)
![Page 41: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/41.jpg)
Optical measurement under magnetic field
(10 Tesla split coils from Cryomagnetic Inc.) Bruker 113v spectrometer
Liquid
He
![Page 42: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/42.jpg)
Josephson Plasma edge
R.H. Yuan et al, Scientific Reports (2012)
Josephson Plasma edge in
K0.75Fe1.75Se2 from nanoscale
phase separation
![Page 43: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/43.jpg)
1000 1500 2000 2500 30000
10
20
30
40
50
60
70
80
90
100
Frequency (cm -1)
Ref
lect
ivit
y (
%)
EuB 6 T=20 K
0 T
1 T
2 T
3 T
4 T
5 T
6 T
7 T
Degiorgi et al., Phys. Rev. Lett. 79, 5134 (1997)
Effect of magnetic field:
Magneto-Optical Reflectivity in EuB6
![Page 44: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/44.jpg)
Quasiparticle relaxation
after optical pump
Pump-probe experiment based on
femtosecond laser
![Page 45: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/45.jpg)
![Page 46: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/46.jpg)
飞秒激光
计算机
锁相放大器
样品、恒温器或磁体系统
太赫兹天线
分光镜
平移台
ZnTe
/4 渥拉斯棱镜
平衡探测器
太赫兹时域光谱系统原理图
硅分光镜
光阑
![Page 47: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/47.jpg)
THz time domain spectroscopy
![Page 48: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/48.jpg)
Optical (e.g. midinfrared) pump, THz probe !
Femtosecond laser can selectively
excite certain modes of correlated
electronic systems, and controllably
push materials from one ordered
phase to another.
Manipulation and control
![Page 49: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/49.jpg)
Science 2011
![Page 50: An introduction to the optical spectroscopy of solidsctcp/China_US_Workshop/Nanlin...An introduction to the optical spectroscopy of solids Nan Lin Wang Institute of Physics Chinese](https://reader036.vdocument.in/reader036/viewer/2022063011/5fc68ab77963bb5fdf4607f9/html5/thumbnails/50.jpg)
Thanks!