sodium x-ray diffraction in the high-pressure regime
TRANSCRIPT
Sodium X-Ray Diffraction in the High-Pressure Regime
X. GongUniversity of RochesterLaboratory for Laser Energetics
59th Annual Meeting of the American Physical SocietyDivision of Plasma Physics
Milwaukee, WI 23–27 October 2017
1
200
400
600
8001000
2000
Tem
per
atu
re (
K)
20 40 60 80 100 200Pressure (GPa)
Liquid
Solid
bcc
Solid
fcc
Solid
cI16
tI19
mP512
oC120tI50
Isentrope
Melting curve
LiquidSolid
aP90
oP8oP8cI16
aP90
hP4
TC13838
A solid hP4 phase of sodium has been observed at ~320 GPa
• Na has been previously observed to transform into an optically transparent phase at 200 GPa*
• The phase is predicted by simulation to be a structurally complex “electride” hP4 structure*
• Na was ramp compressed to ~320 GPa on the OMEGA EP Laser System and studied using in-situ x-ray diffraction
• The existence of the hP4 phase at ~320 GPa indicates that the rise of the melting temperature starting at 120 GPa continues even at higher pressures
2
Summary
* M. Marqués et al., Phys. Rev. B 83, 184106 (2011).
Collaborators
D. N. Polsin, J. R. Rygg, T. R. Boehly, L. Crandall, B. J. Henderson, S. X. Hu, M. Huff, R. Saha, and G. W. Collins
University of Rochester Laboratory for Laser Energetics
R. Smith, J. H. Eggert, and A. E. Lazicki
Lawrence Livermore National Laboratory
M. McMahon
Department of Physics, University of Edinburgh
3
TC13839
At high pressures, Na has a unique melting curve* that possessesa minimum at 120 GPa, then rises steeply
4
200
400
600
8001000
2000
Tem
per
atu
re (
K)
20 40 60 80 100 200Pressure (GPa)
Liquid
Solid
bcc
Solid
fcc
Solid
cI16
tI19
mP512
oC120tI50
Melting curve
aP90
oP8oP8cI16
aP90
*M. Marqués et al., Phys. Rev. B 83, 184106 (2011), and references therein.
TC13840
Diamond-anvil-cell (DAC) experiments* show that Na transformsinto an optically transparent phase at 200 GPa
5
* Y. Ma et al., Nature 458, 182 (2009).
200
400
600
8001000
2000
Tem
per
atu
re (
K)
20 40 60 80 100 200Pressure (GPa)
Liquid
Solid
bcc
Solid
fcc
Solid
cI16
tI19
mP512
oC120tI50
Melting curve
aP90
oP8oP8cI16
aP90
Reflecting
TC13841
Diamond-anvil-cell (DAC) experiments* show that Na transformsinto an optically transparent phase at 200 GPa
6
200
400
600
8001000
2000
Tem
per
atu
re (
K)
20 40 60 80 100 200Pressure (GPa)
Liquid
Solid
bcc
Solid
fcc
Solid
cI16
tI19
mP512
oC120tI50
Melting curve
aP90
oP8oP8cI16
aP90
AbsorbingReflecting
* Y. Ma et al., Nature 458, 182 (2009).
TC13842
Diamond-anvil-cell (DAC) experiments* show that Na transformsinto an optically transparent phase at 200 GPa
7
200
400
600
8001000
2000
Tem
per
atu
re (
K)
20 40 60 80 100 200Pressure (GPa)
Liquid
Solid
bcc
Solid
fcc
Solid
cI16
tI19
mP512
oC120tI50
Melting curve
aP90
oP8oP8cI16
aP90
AbsorbingReflecting Transparent
* Y. Ma et al., Nature 458, 182 (2009).
TC13843
This phase is predicted* to be an “electride” hP4 structure, where conduction electrons are “trapped” in interstitial wells, producing an insulator
8
* Y. Ma et al., Nature 458, 182 (2009).
hP4: a double-hexagonal close-packed (dhcp)structure squeezed along the c axis.
Electron localization function
Na1 Na2
Interstitial
IonElectron
Na2
Na1120°
a a
c c
a b
C
A
C
B
C
TC13844
The powder x-ray diffraction image-plate (PXRDIP)* diagnostic is usedto obtain diffraction data of a compressed powder Na sample
9
Laserdrive
Cu Hea, 1.48 Å
X-raysource
C Na C Tungsten pinholecollimator/reference
VISAR**
Image plates
* J. R. Rygg et al., Rev. Sci. Instrum. 83, 113904 (2012).**VISAR: velocity interferometer system for any reflector
TC13845
The powder x-ray diffraction image-plate (PXRDIP)* diagnostic is usedto obtain diffraction data of a compressed powder Na sample
10
Laserdrive
Cu Hea, 1.48 Å
C Na C
VISAR
Image plates
C Na C
W
W
Target structure
X ray
VISARLaserdrive
Tungsten pinholecollimator/reference
X-raysource
* J. R. Rygg et al., Rev. Sci. Instrum. 83, 113904 (2012).
TC13846
The powder x-ray diffraction image-plate (PXRDIP)* diagnostic is usedto obtain diffraction data of a compressed powder Na sample
11
Laserdrive
Cu Hea, 1.48 Å
X-raysource
C Na C Tungsten pinholecollimator/reference
VISAR
Image platesDelivered target drive and x-raysource drive the pulse shape
Time (ns)0 5 10 15 20 25
Po
wer
(T
W)
100
10–1
10–2
Target driveramp pulse
X-ray spectrometerdrive 1-ns pulse
* J. R. Rygg et al., Rev. Sci. Instrum. 83, 113904 (2012).
TC13847
The powder x-ray diffraction image-plate (PXRDIP)* diagnostic is usedto obtain diffraction data of a compressed powder Na sample
12
* J. R. Rygg et al., Rev. Sci. Instrum. 83, 113904 (2012).
Laserdrive
Cu Hea, 1.48 Å
X-raysource
C Na C Tungsten pinholecollimator/reference
VISAR
Image plates
Debye–Scherrer powder diffraction
Line x-ray sourceCompressed randomly
oriented crystalsd1
2θ2
2θ1
Debye–Scherrer
rings
2θ1
2θ2
Debye–Scherrer
ringsd1
Line x-ray sourceCompressed randomly
oriented crystals
TC13848
VISAR data are used to determine the velocity of the diamond free surface,which is back-propagated to determine the pressure in the Na sample
13
10 15 20 25 30 35
Time (ns)
12
10
8
6
4
2
0
–2
Vel
oci
ty (
km/s
)
VISAR raw dataFree surface
Diamond window free-surface velocity
VISAR
So
diu
m58
nm
Dia
mo
nd
win
do
w77
nm
Dia
mo
nd
ab
lato
r40
nm
340
320
300
280
260
240
220
Pre
ssu
re (
GP
a)
18 20 22 24 26
Time (ns)
TC13849
Raw diffraction data are scanned from image plates on five sides of the box and projected onto a {–2i plane
14
X-raysource
Image plates
VISAR
40 50 60 70 80 90
150
100
50
0
–50
–100
–150
( )°2i
()°
{
The four brightest lines are tungsten bcc* diffraction signals,which are used for calibration
TC13850
15
* bcc: body centered cubic
40 50 60 70 80 90
150
100
50
0
–50
–100
–150
Calibration lines
( )°2i
()°
{
40 45 50 55 60 65 70
W W W0.20
0.15
0.10
0.05
0.00
Inte
nsi
ty
2i (°)
TC13851
The three weaker lines are sodium diffraction lines,consistent with hP4 structure
16
40 50 60 70 80 90
150
100
50
0
–50
–100
–15043.3°
60.9°Sodium diffraction
lines
65.7°
( )°2i
()°
{
40 45 50 55 60 65 70
Na(011)
Na(012)
Na(110)
0.20
0.15
0.10
0.05
0.00
Inte
nsi
ty
2i (°)
TC13852
The three weaker lines are sodium diffraction lines,consistent with hP4 structure
17
40 50 60 70 80 90
150
100
50
0
–50
–100
–15043.3°
60.9°Sodium diffraction
lines
65.7°
( )°2i
()°
{
Na2
Na1120°
a a
c c
a b
C
A
C
B
C
a = 2.73 Åc = 3.72 Åc/a = 1.36t = 6.36 g/cm3
t/t0 = 6.57
Sodium has a solid phase at ~320 GPa, which is consistent with hP4 structure
TC13853
18
Na2
Na1120°
a a
c c
a b
C
A
C
B
C
hP4
200
400
600
8001000
2000
Tem
per
atu
re (
K)
20 40 60 80 100 200Pressure (GPa)
Liquid
Solid
bcc
Solid
fcc
Solid
cI16
tI19
mP512
oC120tI50
Isentrope
Melting curve
aP90
oP8oP8cI16
aP90
TC13854
The melting temperature rises at >120 GPa
19
Na2
Na1120°
a a
c c
a b
C
A
C
B
C200
400
600
8001000
2000
Tem
per
atu
re (
K)
20 40 60 80 100 200Pressure (GPa)
Liquid
Solid
bcc
Solid
fcc
Solid
cI16
tI19
mP512
oC120tI50
Isentrope
Melting curve
LiquidSolid
aP90
oP8oP8cI16
aP90
hP4
TC13838
A solid hP4 phase of sodium has been observed at ~320 GPa
20
Summary/Conclusions
• Na has been previously observed to transform into an optically transparent phase at 200 GPa*
• The phase is predicted by simulation to be a structurally complex “electride” hP4 structure*
• Na was ramp compressed to ~320 GPa on the OMEGA EP Laser System and studied using in-situ x-ray diffraction
• The existence of the hP4 phase at ~320 GPa indicates that the rise of the melting temperature starting at 120 GPa continues even at higher pressures
* M. Marqués et al., Phys. Rev. B 83, 184106 (2011).