Electron-Lattice interaction under high pressure
by single-crystal diffraction study
Pressure-induced structure change
due to electron-spin-lattice interaction under extreme condition
charge displopornation
orbital rearrangement
spin-Peierls transition
charge transfer
Jahn-Teller transition
Motto transition
density of state change
high-low spin transition
magneto distortion
etc.
Experiments
1. Possible spin cross over and electron configuration change
of Mn2O3 detected by X-ray emission spectrum analysis.
2. Difference in Jahn-Teller distortion of Fe2TiO4 ulvöspinel at
high pressure and at low temperature by MEM .
3. Anisotropy of Electric conduction in FeTiO3
with increasing pressure.
collaborators
Akira Yoshiasa
Osamu Ohtaka
Takaya Nagai
Taku Okada
Yuki Nakamoto
Department of Geoscience Kumamoto University
Department of Earth and Space Science Osaka University
Department of Geology Science Hokkaido University
Institute of Solid State Physics University of Tokyo
Center for quantum Science and Technology
under extreme conditions Osaka University
Ho-Kwang Mao Carnegie Institute of Washington
Russel Hemley Carnegie Institute of Washington
Wendy Mao
Stanford University
Graduate Students
Department of Earth and Space Science Osaka University
Takanori Hattori
Taku Tsuchiya
Jun Tsuchiya
Hironori Nomori
Yutaka Komatsu Tetsuro Mine
Hiroaki Uchida
Hiroaki Sugita
Yukiko Asogawa
and many others
Octahedral
by Jahn-Teller
effect
Polyhedraldistortion
deformation
by Jahn-Teller
effect
3d4 (Mn3+, Cr4+, Fe4+ )
3d9 (Cu2+)
Strong CFSE effect in the cubic - to- tetragonal transition
Cubic
Tetragonal
↑
↑↑↑
structure
↑
・
Tetragonal
dx2 - y 2
↑
dz2
↑↑↑
・・・
elongation octahedra
c/a>1
↑
・
dz2
dx2 - y 2
・・・
flattened octahedra
c/a<1
Week CFSE effect in the cubic - to- tetragonal transition 3d2 (Ti2+, V3+, Cr4+ )
3d7 (Co2+, Ni3+)
Cubic
Tetragonal
Tetragonal
↑↑
↑ ↑
dxy
↑↑
dxz, dyz
structure
dxy
↑
・・
dxz, dyz
elongation octahedra
c/a>1
dxz, dyz
↑
↑
dxy
dxz, dyz
・・
↑
dxy
flattened octahedra
c/a<1
X-ray emission spectra of transition elements
X-ray fluorescence lines
N7
N1
d electron
M5
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M
L
K
β1
β3 β2
K
Kα
K
α1 β1
L α2 β2,15
M1
L3
L2
L1
α1
α2
K
Energy
Energy diagram of 3d4
Tanabe-Sugano Diagram
t22g
T
｝
｝
6Dq
Eegg
｝
｝
t
T2g
4Dq
10Dq
10Dq
4Dq
6Dq
e
Eg
2g
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0
d4, d9 in Oh
d1, d6 in Td
d1 :
d4 :
d6 :
d9 :
d4, d9 in Td
d1, d6 in Oh
Ti3+ V4+ Cr5+
Cr2+ Mn4+ Fe5+
Fe2+ Co3+ Ni4+
Cu2+
D/B
Mn2O3 high-pressure transition
600
B
Three polymorphs
at ambient temperature
550
Y A x is T it le
500
Monoclinic Gd2O3
450
23GPa
after laser heating
B
450
400
B
Y A x is T itYleA x is T it le
700
400
350
post perovskite
25GPa
600
300
350
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500
ǙDZÇÃÉsÉNÉ`ÉÉǾå©ÇÈǞǽDžÇÕïKóvÇ-Ç Å250
300
400
6
8
10
12
14
16
18
X Axis Title
bixbyite
250
300
14 GPa
200
200
6
8
100
10
12
14
16
18
20
X Axis Title
66
88
10
10
12
12
X Axis Title
14
14
16
16
2θ (λ=0.39640Å)
18
18
Selected M2O3 structure type and rM/rO ion radius ratio.
corundum structure
R3c
mineral name a (Å) c (Å)
Z.
-Al2O3 corundum 4.7628 13.0032 13
----------5.148 13.636 22
Ti2O3
V2O3
karelianie 5.105 14.449 23
Cr2O3
eskolite
4.957 13.584 24
-Fe2O3 hematite
5.035 13.72
26
Z=6
r(M) / r(O)
0.489
0.587
0.565
0.547
0.500
rare earth C-type structure
Ia 3
mineral name
a (Å)
Z.
Sc2O3
9.845
21
* Mn2O3 bixbyite
9.4088
25
---------10.604
39
Y2O3
In2O3
---------10.118
49
La2O3 ---------11.38
57
---------11.136
59
Pr2O3
11.048
60
Nd2O3 ---------Sm2O3 ---------10.990
62
10.840
63
Eu2O3 ---------Gd2O3 ---------10.798
64
Dy2O3 ---------10.667
66
10.866
68
Er2O3 ---------10.604
69
Tm2O3 ---------Yb2O
---------10.439
70
*bearing a little amount of Fe2O3 component.
Z denotes the atomic number.
Z=16
r(M) / r(O)
0.643
0.521
0.753
0.681
0.849
0.819
0.814
0.796
0.788
0.781
0.762
0.746
0.739
0.730
Bixbyite structure
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Mn1
Mn2
SG: Ia3- z=16
a = b = c = 9.4142Å
M1 8a 3 6-fold
M2 24d .2. 6-fold
Mn2O3 of post -perovskite phase at 32.5GPa
Mn2O3Data.QDA
MgSiO3
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[010]
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Mn2O3
10
15
20
[010]
[101]
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SG: Cmcm z = 4
25
30
a=2.7498
b=9.0189 c=6.7711Å
Mn1 4c m2m 6-fold
Mn2 4a 2/m 8-fold
Mn2O3 of monoclinic Gd2O3 type phase at 23 GPa
after laser heating
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NaCl
NaCl
Mn1
NaCl
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Mn2
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Mn3
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Gd２O3
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4
6
8
1 0
1 2
A x is T it le
2θX (λ=0.369402Å)
1 4
1 6
1
X-ray Emission Spectroscopy
set up at APS 16ID-D
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detection of spin state and charge
displopornation
diamnond anvil
floerescence
analyzer
monochlomater
Si
Si (333)
CCD detector
X-ray emission spectra of various Mn oxides
High-spin state at ambient conditions
4+
(Mn )
Nominal spin
Normalise Intensity
3
5
●
2
●
●
1
3
MnO2
6490
3+
Mn2O3 (Mn )
MnO
4
Mn2O3
Kβ 1,3 position (eV)
2+
3
33d5
d
6475
6480
6492
6485
6490
Fluorescence Energy (eV)
6495
3
3
(t2g
2g
Kβ 1,3
6470
1
MnO (Mn )
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6491
3
3d (t2g eg )
Kβ '
6465
2
3
0
3d
3d3 (t(t2g
2g egg )
6500
0
eegg2))
X-ray emission spectrum of Mn2O3
23.4
Normalized Intensity
1.0
23.6
0.8
No high-low spin transition
High-spin
state
23.8
of VIMn3+
No charge displopornation.
24.0
0.6
24.2
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0.4
24.6
0.2
24.8
Kβ ’
0.0
Kβ13
( 2θ )
6460
6470
6480
6490
6500
6510
6520
( eV )
Strong Jahn-Teller effect on the tetrahedral site
by single-crystal diffraction study under
low-temperature and high-pressure
Sample :
Fe2TiO4 ulvöspinel
Inverse spinel structure (Fe2+)[Fe2+,Ti4+]O4
Fd3m z=8 a=8.5297Å
antiferromagnetic
Jahn-Teller
cationionininthe
tetragonal
Jahn-Teller
the tetrahedral
site spinels
(A site)
A
Sample
type
stability
J-T ion
configuration
c/a
MgTi2O4
Inverse
T<260K
Ti3+ (3d1)
ε (dx2-y2)
0.996
Inverse
T<142K
Fe2+ (3d6)
ε (dz2)
1.05
ε (dx2-y2)
0.998
B
(Ti3+) [Mg2+,Ti3+]O4
Fe2TiO4
A
B
(Fe2+) [Fe2+,Ti3+]O4
CuCr2O4
A
7<P<11GPa
Normal
T<893K
Cu2+ (3d9)
ε (dx2-y2)
0.915
Normal
T<299K
Ni2+ (3d8)
ε (dz2)
1.032
Normal
T<2303K
Ni2+ (3d8)
ε (dz2)
0.907
0<P<12GPa
Mn3+ (3d4)
ε (dz2)
******
Fe2+ (3d6)
ε (dz2)
B
(Cu2+) [Cr3+]2O4
NiCr2O4
A
B
(Ni2+) [Cr3+]2O4
NiMn2O4
A
B
(Ni2+) [Mn3+]2O4
CoFe2O4
A
B
(Ti3+) [Mg2+,Ti3+]O4
Inverse
1.17
High pressure experiment
tightening
screw
stopper screw
positioning
pin
80°
gasket
200μm thick
SUS
backing plate
SUS 306
sample room
150μmφ
x 60μm thick
Low temperature experiment
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Lattice constant change
Low-temperature experiment
High-pressure experiment
at 20℃
at 1atm
(1) Transition temperature of
cubic-to-tetragonal at -110℃
Å
8.55
(2) c/a = 1.0035(5) at -170℃.
c
●
●
●
●
●
●
8.53
a
●
8.51
5
.3
8
6
4
2
0
resu
P
a
●
●
a
8.49
Cubic
Tetragonal
8.47
8.45
8.43
●
●
8.49
8.47
(2) c/a = 0.9982(4) at 11.43GPa.
Å
8.55
8.53
8.51
(1) Transition pressure of
cubic-to-tetragonal at 9 GPa.
Tetragonal
●
8.45
Cubic
●
●
8.43
8.41
8.41
8.39
8.39
8.37
8.37
8.35
-200
8.35
-150
-100
-50
Temperature (℃)
0
50
●
a
●
●
c
0
2
4
6
8
10
Pressure (GPa)
●
●
●
●
12
14
Polyhedral relative volume change
Low-temperature experiment
High-pressure experiment
at 20℃
at 1atm
1.02
1.02
.
octahedron
1.00
●
●
unit cell
●
●
0.98
●
●
●
●
1.00 ●
●
●
●
●
●
●
●
●
tetrahedron
Cubic
●
●
Tetragonal
●
●
0.98
●
●
●
●
●
●
octahedron
●
●
0.96
0.96
●
●
unit cell
0.94
0.94
●
●
●
Cubic
Tetragonal
●
●
●
●
●
●
tetrahedron
●
●
●
0.92
-200
0.92
-150
-100
-50
0
Temperature (℃)
50
0
2
4
6
8
Pressure (GPa)
10
12
14
a=6.0263Å
Difference Fourier Map ( -170℃)
z
tetragonal phase
contour : 0.2e/Å3
b=6.0263Å
Residual electron density
y
x
dx2-y 2
a=6.0263Å
IVFe
0.637Å
z
IVFe
b
O
VI(Ti,Fe)
×
x
y
on to (001) z=0.125
a
dz2
O
VI(Ti,Fe)
O
a
on to (100) y=0.25
×
O
O
c
O
O
on to (001) z=0.5
b=6.0263Å
×
O
c=8.5035Å
VI(Ti,Fe)
×
Electron density by Maximum-Entropy Method (MEM)
r
r
r
r r ⎤
⎡ λ Fo
r
r
w(h )
r Fobs ( h ) − Fcal ( h ) exp( − 2π ih ⋅ ri ) ⎥
ρ ( ri ) = τ ( ri ) exp ⎢
∑
2
r
⎣ N h σ (h )
⎦
{
}
r
r r
r
Fcal ( hF)obs=, V(F
∑obsρ)( ri ) exp( − 2π ih ⋅ ri )
C =
i
Space group
Fcal
1
∑
N hr
ρ
τ (initial electron
density )
r
r 2
Fcal ( h ) − Fobs ( h )
r
2
σ h
MEM
solution
()
C=1
Iteration
Initial information
Weighted electron density
r
⎡
r r ⎤
r
r ⎫⎪
r
r
⎧⎪
⎥
⎢ λF0
w(
h
)
ρ ( r j ) = τ ( r j )exp ⎢
⎨ F obs ( h ) − F cal ( h ) ⎬ exp( −2 π i h ⋅ r j )⎥
r
∑
r
⎪
⎪⎭
⎥⎦
⎢⎣ N
h σ 2 (h ) ⎩
r
w( h ) :
weight
r
(1) w( h ) = 1
r
r
r n
1
(2) w( h ) = Fobs ( h ) n = ,1,2
2
σ ( h ) : estimated error
:
r
−n
r
1
⎛ sin θ ⎞
(3) w ( h ) = ⎜
n = ,1,2
⎟
2
⎝ λ ⎠
⎛ sin θ ⎞
⎟+b
⎝ λ ⎠
σ (h ) = a × ⎜
MEM electron density map on to (110)
Low temperature
Ambient condition
z
IVFe2+
x
-50 °C
cubic
y
-100 °C
cubic
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oxy
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IVFe
2+TI4+
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Dz
-150 °C
tetragonal
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-170 °C
tetragonal
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z
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x
y
High pressure
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8.76GPa
cubic
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Spinel structure
asymmetric unit
9.84GPa
cubic
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10.54GPa
tetragonal
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11.43GPa
tetragonal
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MEM electron density map on to (110)
Low temperature
Ambient condition
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-100 °C
cubic
-150 °C
tetra
-170 °C
tetra
y
VI(Fe2+,Ti4+)
High pressure
x
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TIFFÅiLZWÅj êLí£ÉvÉçÉOÉâÉÄ
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ÅB
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Å
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9.84GPa
cubic
10.54GPa
tetra
11.43GPa
tetra
O-Fe-O of Fe2+O4 tetrahedral bond angle
Low temperature
High pressure
110.2
110.2
●
β
α=β
●
●
109.4
109.4
●
ū
●
●
●
109.0
109.0
α
108.6
108.6
cubic
tetragonal
108.2
108.2
-200
-200
●
109.4
●
109.4
-150
-100
-50
-100
-50
Temperature
α
O-Fe-O
0
0
( C)
α=β
●
α
●
●
●
●
●
β
109.0
109.0
108.6
108.6
cubic
108.2
-150
●
●
108.2
Temperature (
β
O-Fe-O
109.8
109.8
Bond angle ( )
●
●
Bond angle ( )
109.8
109.8
Bond angle ( )
Bond angle ( )
ū
110.2
110.2
50
0
0
ū)
2
2
4
4
tetragonal
●
6
6
8
8
10
10
12
12
Pressure
(GPa)
Pressure
(GPa)
High Pressure Low Temperature
d z2,
d x2-y2
d xy,dyz,d zx
or
d z2,
d x2-y2
tetragonal (42m)
tetrahedral configuration
d z2,dx 2-y2
cubic (43m) (m3) (23)
tetrahedral configuration
14
14
Anisotropy of electric conduction in ilmenite
under high pressure
electron hopping by super exchange
Sample :
FeTiO3 ilmenite
R3 z= 6 hexagonal a= 5.0881Å c= 14.9 10Å
Electric conduction of FeTiO3 ilmenite
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[001]
[001]
[001]
[001]
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ÅB
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Electron density (eÅ-3)
Radial distribution of electron density distribution
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Z-coordinate
Z-coordinate
along <001>
[001]
[001]
[110]
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Conclusion
1. Mn2O3cof cubic bixbyite structure is transformed to postperovskite structure over 21GPa and Jahn-Teller effect in
the structure is suppressed under pressure.
2. After laser heating 1400 C, the post-perovskite structure is
changed monoclinic Gd2O3 structure.
3. X-ray emission spectrum analysis proved these transitions
are not induced from high-low spin transition or charge
displopornation.
4. From MEM electron density distribution analysis, the JahnTeller distortion caused by IVFe2+ of Fe2TiO4 ulvöspinel
is different between at high pressure and low temperature.
Electron configurations in e-orbit and t2 are different in
these conditions.
5. Anisotropy of Electric conduction in FeTiO3 was confirmed
with increasing pressure.
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Electron
of transition
transitionelement
elements
Electronspin
spinconfiguration
configuration of
in cubic symmetry
8-fold coordination
hexahedron
dxy dyz
8-fold coordination
antidipiramid
dx2-y2
dz2
dxz dx2-y2
dxy
dz2
dyz dxz
5-fold coordination
rhombohedron
dz2
d2 2
dxy x -y
dxz dyz
4-fold coordination
tetrahedron
−
4 32
6-fold coordination
octahedron
tetragonal dipiramid
5-fold coordination
trigonal dipiramid
dz2 dx2-y2
dz2
−
dxy dx2-y2
4
m
32
m
dxy dxz dyz
4-fold coordination
coplanar square
dxz dyz
3-fold coordination
coplanar trigon
dx2-y2
dx2-y2
dxy dxz dyz
dxy
dz2 dx2-y2
dz2
dxz dyz
dxy
dxz dyz
dz2