High Pressure study of Bromine

Shimizu LabM1 　 Hayashi Yuma

Contents• Introduction Iodine• Bromine• Summary• Next plan

Introduction

http://www.cqst.osaka-u.ac.jp

room –temperature superconductor?

High-Pressure Effect

MoleculeInsulator

pressurization pressurization monatomic metal

molecular dissociation ( 分子解離 )

( 単原子金属 )

Applying pressure means…

Electronic states change.

The atomic distance becomes closer.・ Structural transition・ Insulator-Metal transition

introduction

　　 Structural phase transition of iodine

• molecular• insulator

I phase

Ambient pressure

・ atomic ・ metal

Y. Fujii, K. Hase, N. Hamaya, Y. Ohishi, A. Onodera, O. Shimomura, and K. Takemura, Phys. Rev. Lett. 58, 796 (1987).

B. Albert, K. Schmit, Z. Anorg. Allg. Chem. 627, 809 (2001).

Molecular dissociation @21GPa

High pressure

introduction

body-centered-orthorhombic

body-centered-tetragonal

face-centered-cubic

Electrical property of Iodine in high pressure

N. Sakai, K. Takemura and K. Tsuji, J. Phys.Soc. Jpn. 51, 1811 (1982).

0 10 20 30 40 500.0

0.5

1.0

1.5

2.0

R/R

50K

T (K)

12 GPa

13 GPa

14 GPa

16 GPa

18 GPa

iodine

The temperature dependence of electrical resistance of iodine becomes positive at 14-16 GPa, indicating insulator to metal transition

introduction

Superconductivity of iodine

K. Shimizu et al., J. Phys. Soc. Jpn., 61, 3853 (1992).

Iodine becomes superconductor in phase at about 1.2 K.Ⅱ

introduction

Hall Effect of Iodine

・ The carrier of iodine is ‘hole’.

[top view]

I- I+

V- V+

V0

B

introduction

T. Yamauchi et al., J. Phys. Soc. Jpn., 63, 3207-3209 (1994).

RH ＝

（ n ： carrier density ）

Tc∝θDexp[-1/N(0)V ]

introduction

Phase diagram of iodine

Crystal structure Molecular phase ( )Ⅰ

Monatomic phase

0

Pressure [GPa]

21

Insulator metal

Superconductor

16

R.T.

Electrical

characteristic

43 55

( )Ⅱ ( )Ⅲ ( )Ⅳ

Molecular 　 dissociation

introduction

・ The carrier of iodine is ‘hole’.

・ Iodine becomes superconductor in phase at about 1.2 K.Ⅱ

Ⅴ phase between and phase Ⅰ Ⅱat 24-25 GPa

K. Takemura et al., Nature 423, 971 (2003).

・ incommensurate structure

・ metal

( )Ⅴ

Crystal structure Molecular phase ( )Ⅰ

Monoatomic phaseR.T.

( )Ⅱ ( )Ⅲ ( )Ⅳ

introduction

Introduction

http://www.cqst.osaka-u.ac.jp

room –temperature superconductor?

High-Pressure Effect

MoleculeInsulator

pressurization pressurization monatomic metal

molecular dissociation ( 分子解離 )

( 単原子金属 )

Applying pressure means…

Electronic states change.

The atomic distance becomes closer.・ Structural transition・ Insulator-Metal transition

introduction

　　 Structural phase transition of iodine

• molecular• insulator

I phase

Ambient pressure

・ atomic ・ metal

Y. Fujii, K. Hase, N. Hamaya, Y. Ohishi, A. Onodera, O. Shimomura, and K. Takemura, Phys. Rev. Lett. 58, 796 (1987).

B. Albert, K. Schmit, Z. Anorg. Allg. Chem. 627, 809 (2001).

Molecular dissociation @21GPa

High pressure

introduction

body-centered-orthorhombic

body-centered-tetragonal

face-centered-cubic

Electrical property of Iodine in high pressure

N. Sakai, K. Takemura and K. Tsuji, J. Phys.Soc. Jpn. 51, 1811 (1982).

0 10 20 30 40 500.0

0.5

1.0

1.5

2.0

R/R

50K

T (K)

12 GPa

13 GPa

14 GPa

16 GPa

18 GPa

iodine

The temperature dependence of electrical resistance of iodine becomes positive at 14-16 GPa, indicating insulator to metal transition

introduction

Superconductivity of iodine

K. Shimizu et al., J. Phys. Soc. Jpn., 61, 3853 (1992).

Iodine becomes superconductor in phase at about 1.2 K.Ⅱ

introduction

Hall Effect of Iodine

・ The carrier of iodine is ‘hole’.

[top view]

I- I+

V- V+

V0

B

introduction

T. Yamauchi et al., J. Phys. Soc. Jpn., 63, 3207-3209 (1994).

RH ＝

（ n ： carrier density ）

Tc∝θDexp[-1/N(0)V ]

introduction

Phase diagram of iodine

Crystal structure Molecular phase ( )Ⅰ

Monatomic phase

0

Pressure [GPa]

21

Insulator metal

Superconductor

16

R.T.

Electrical

characteristic

43 55

( )Ⅱ ( )Ⅲ ( )Ⅳ

Molecular 　 dissociation

introduction

・ The carrier of iodine is ‘hole’.

・ Iodine becomes superconductor in phase at about 1.2 K.Ⅱ

Ⅴ phase between and phase Ⅰ Ⅱat 24-25 GPa

K. Takemura et al., Nature 423, 971 (2003).

・ incommensurate structure

・ metal

( )Ⅴ

Crystal structure Molecular phase ( )Ⅰ

Monoatomic phaseR.T.

( )Ⅱ ( )Ⅲ ( )Ⅳ

introduction

Structural phase transition of bromineMolecular dissociation near 80 GPa

Y. Fujii et al.,Phys. Rev. Lett. 63, 536(1989)

Electrical property of bromine

K Amaya et al 1998 J. Phys.: Condens. Matter 10 11179

Above 90GPa, small drops in electrical resistance are observed, which show the onset of superconductivity.

Summary

• Bromine has molecular dissociation near 80GPa.

• Under high pressure, bromine has the same structure changes as iodine.

• At pressure higher than 90GPa, small drops in electrical resistance are observed, which show the onset of superconductivity.

Next plan

I will perform electrical resistance measurement of solid bromine at high pressure again,

Because pressure measurements above 140 GPa may be incorrect.

How to estimate pressure

Ruby produces fluorescence when irradiated by laser. The wavelength of the peak changes with pressure.

For P < 100 GPa : Ruby Fluorescence （ルビー蛍光法）

For P > 100 GPa : Raman Spectroscopy ( ラマン分光法）

　　 P = 66.9 - 0.5281ν + 3.585×10-4 ν2

Irradiate diamond with laser. On applying pressure, the vibration of C-C bond in diamond changes, the

wavelength of scattered light becomes small.