Electron Poor Materials Research Group EPM RG Updates of Experiments in Augsburg --- Crystallographic study of SiB 3, ZnSb… --- Synthetic attempts for.
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Electron Poor Materials Research Group
EPMRG
Updates of Experiments in Augsburg
--- Crystallographic study of SiB3, ZnSb…
--- Synthetic attempts for B
--- Property measurements of
(ZnSnSb2)1-x(InSb)2x
Charge Density Study by the Analysis of High Resolution Diffraction Data
• Bruker AXS diffractometer with Imus micro-focus X-Ray Source
• Ag-radiation, the same sinat much lower angle
• Enough data redundancy for good statistics
Multipole Refinement of ZnSb in Jana 2006
• Diffraction data were collected at 100K with 2 up to 120o
• Extinction and anharmonicity were refined before starting the multipole refinement
• d electrons of Zn were considered as valence electrons
• Multipole refinment was stopped at 2nd order (quadruple)
• R=1.38% and highest peak of 0.34 e/Å3
e 3 = 0 . 0 0 0
- 4 . 0- 2 . 00 . 02 . 04 . 0e 1- 4 . 0
- 2 . 0
0 . 0
2 . 0
4 . 0
e 2
Total Density
Total Laplaciane 3 = 0 . 0 0 0
- 3 . 0- 1 . 01 . 03 . 05 . 0e 1- 4 . 0
- 2 . 0
0 . 0
2 . 0
4 . 0
e 2
+/- 8, 4 , 2 * 10^n and n is +/- 3, 2, 1.
Dumbbell Rattling?
50 100 150 200 250 300
T (K)
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
C/T
3 (mJ/m
olK
4 )
ZnS b
50 100 150 200 250
T (K)
0.01
0.02
0.03
0.05
0.1
0.2
0.3
0.5
1
2
3
C/T
3 (mJ/m
olK
4 )
Zn4S b3
85% D = 250.8 K
+ 15% T E = 59.6 K 85% D = 257 K
+ 15% T E = 57.6 K
Heat Capacity of ZnSb
0 50 100 150 200 250 300 3500
100
200
300
400
500
Cp/
T (
mJ/
mol
K2)
T (K)
C/T_ZnSb Cal C/T_ZnSb
0 50 100 150 200 250 3000
10000
20000
30000
40000
50000
Cp
(m
J/m
olK
)
T (K)
ZnSb Cal_ZnSb
Synthesis of - SiB3 with high pressure
a
b
BSiGe
Si1-xGexB3
Si2: 90% Ge2: 10%
Si1: 84% Ge1: 16%Si1: 84% Ge1: 16%Si1: 84% Ge1: 16%
Thermoelectric Chalcopyrite
(ZnSnSb2)1-x(InSb)2x + 4Sn
x = 0.9, x = 0.85, x=0.8 and InSb (quenched from 1:1 melt and Sn-flux growth)
0 50 100 150 200 250 300 350
-200
-100
0
100
200
300
400
Th
erm
op
ow
er
(V
/K)
T (K)
Insb_Augsburg_heating_4p InSb_Agusburg_cooling_4p InSb_ASU_Sn Flux_2p InSb_ASU_Quenched_2p
InSb Seebeck
All Seebecks from Augsburg’s work
0 50 100 150 200 250 300
0
10
20
30
40
50
60
70
The
rmop
ower
(V
/K)
T (K)
x=0.9_Augsburg_4p x=0.85_Augsburg_2p x=0.8_Augsburg_2p
All TCs from Augsburg’s work
0 50 100 150 200 250 3000
1
2
3
4
Th
erm
al C
ondu
ctiv
ity (
W/m
K)
T (K)
x=0.85_Augsburg_2p x=0.8_Augsburg_2p x=0.9_Augsburg_4p
InSb_Sn Flux
All Resistivities
0 50 100 150 200 250 3000
5
10
15
20
x=0.9_Augsburg_2p x=0,9_ASU_4p x=0.85_Augsburg_2p x=0.8_ASU_4p x=0.8_Augsburg_2p
Re
sist
ivity
(mc
m)
T(K)
Acknowledgement
Dr. Wolfgang Scherer Dr. Ernst-Wilhelm Scheidt
Dr. Georg Eickerling Dr. Francisco J. Garcia-Garcia
Christoph Hauf Andreas Fischer
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