マテリアルズインフォマティクスの現状と将来展望

1京都大学
2京都大学

工学研究科

材料工学専攻構造材料元素戦略拠点(ESISM)

3ﾌｧｲﾝｾﾗﾐｯｸｽｾﾝﾀｰ(JFCC)

ナノ構造研究所

4 NIMS 情報統合型物質・材料研究拠点(MI2I)

田中 功

米国のチャレンジ

2011 June
材料ゲノム：アメリカ製造業のルネサンスへ

To double the speed with which we discover, develop, and manufacture newmaterials. 新材料の発見・開発・製品化のスピードを２倍に．
FY12 budget includes $100 million to launch the Materials Genome Initiative.
年間予算 1億USドル = 120億日本円
2

3

EUのチャレンジ１

http://nomad-lab.eu/

EUのチャレンジ２

Swiss National Science Foundation

日本のチャレンジ
2012 科学研究費・新学術領域『ナノ構造情報』
2013『マテリアルズ・インフォマティクス』
JSTでの調査採択

2014

実施中
2015
NIMSｲﾉﾍﾞｰｼｮﾝﾊﾌﾞ開始

JSTさきがけ開始

2016

20176マテリアルズインフォマティクス
マテリアルズサイエンスの常法
材料設計

ニーズ
合成実験

形成エネルギー（第一原理計算）

情報論的学習理論

特性解析実験

シーズ

最適化

Ceの単一原子ｼﾐｭﾚｰｼｮﾝ

理論計算
物理法則：

解析

古典力学，電磁気学，熱・統計力学，量子力学等に立脚（無機）材料科学のキャストの例： 結晶性物質

Allight metal tube
face centered cubic structure

Periodic Table

NaClrock salt structure

table salt

BaTiO3
perovskite structure

ferroelectrics

Enormous number of chemical combinations

Periodic Table

Number of chemicalelements

Number ofchemical combinations(only for simple composition ratio)

1234~100~100,000~10,000,000~1,000,000,000
9Inorganic Crystal Structure Database (ICSD)World largest databasefor known inorganic crystals.
177,000 crystal structures 55,000 structures
excluding duplicates.
9,100 structure prototypes(e.g. rock-salt, perovskite, ...)
Number ofchemical elements

Number ofstructure prototypes in ICSD

12
3
4

120
1,700
4,700
4,300

10

First Principles Calculations
Useful to fill the gap between enormous number ofchemical combinations and experimental database.
Electronic structure calculations entirely based on
quantum theory without using empirical parameters.
Total energy
Force/Stress
Electronic/Magnetic structures
Physical properties
・・・・

11

First Principles Calculations
INPUTSpace Group
Unit Cell Parameters

Density Functional Theory Calculations
 1 2    Vion ( r )  2  ( r ' )   dr ' v XC ( r )  i ( r )   i  i ( r )r  r'OUTPUT
Total Energy
Stress / ForceElectronic Structures

Computational Cost 0 (CC0)structure optimization

Atoms / Atomic Number and Coordinates
SrTiO3(cubic perovskite)
Space Group3

1 x Sr + 1 x Ti + 3 x O= 5 atoms/unit cellComputational Cost
CC0 x 10 = CC112

Cost for First Principles Calculations
CC0 1minSingle shot GGA

PC cluster
5 nodes x 20 cores =100 cores

Computational Cost with 1 core

1hour
CC22x2x2 supercell Single shot GGA

CC3 1dayPhonon frequency

CC4 1 week

Lattice thermal conductivity
CC5
1 yearDiffusivity by FPMD simulation
1000 atoms cell Single shot GGA

price ~ USD30k (JPY 4M)

1min

Computational Cost with 100 cores

Structure opt.

CC11hour

10 nodesCC5 1dayCC6 1 week
CC71 year13

A set of DFT calculations during a lunch breakcubic perovskite

Number of compounds: 530

CC1 x 530 calculations
by a 100 core PC cluster

14

Materials Project @MIThttps://materialsproject.org/

ICSD収録の構造データについて，生成エネルギーやバンドギャップなどの第一原理計算結果

15

Materials Project @MIThttps://materialsproject.org/

ICSD収録の構造データについて，生成エネルギーやバンドギャップなどの第一原理計算結果

Discovery of new low thermal conductivity
materials
First-Principles Anharmonic Lattice-Dynamics Calculations
and Bayesian Optimization

Atsuto Seko, Atsushi Togo, Hiroyuki Hayashi,
Koji Tsuda, Laurent Chaput, and IT
A. Seko, A. Togo, H. Hayashi, K. Tsuda, L. Chaput, and IT PRL 115, 205901 (2015)17

Discovery of ultra-low thermal conductivity
materials of 0.1W/m·K level
in ICSD database (55,000 crystals)
diamond

Thermal conductivity (W/m·K)>2000

Thermal conductivity

18

Background
Thermal Conductivity (TC)
κ = κelectonic + κlattice
Lattice Thermal Conductivity (LTC) Reliable experimental dataset is limited ( < 100 crystals).
 Reliable first principles calculations are very expensive.
(CC5 class : 1 day/100 cores for 1 simple crystal.) Little knowledge to predict LTC deductively.
(Chemistry-structure-LTC relationships are not clear.)Materials search has been made through “modification” ofknown compounds showing high/low LTC.
19

Thermoelectric materials
Essential for utilizing otherwise waste heat.

PowerLow T
Electric current

Heat flux

p-typen-typeElectric current

Figure ofMerit

Electric current

High T∶ Seebeck coefficient: electrical conductivity: thermal conductivity

20Physical origin of thermal resistivity
Phonon-phonon scattering (phonon anharmonicity)
Harmonic phonons do not interact.

qphononq''q'phonon21

phonopy： open source for ab-initio phonon calcs
http://phonopy.sf.net/Phonon dispersion

Entropy
CVFree Energy

Atsushi TOGO
Kyoto Univ.
VolumeThermalExpansion

Web of Science 2015 Oct

Number of citations

Free Energy

Year

22

Lattice Thermal Conductivity (LTC)@300K
First principles calculation vs. Experimental data
CC5 class : 1 day by 100 coresfor 1 simple crystal

Reliable calculations
whose accuracy arecomparable toexperiments!
23

Virtual Screening

24

Correlations between LTC and predictors
CC5 classCC1 classCC3 class25

Candidates of descriptors for LTC
Model 1: Volume V and Density ρModel 2: Model 1 + primitive elemental descriptors
HLiBeBCNOFLiH

11000000LiF01000001BeO00100010BN00010100······

26

Toward discovery of new low LTC materials
Kriging
Interpolation method for which the interpolated values are modeled by aGaussian process governed by prior covariances, originally from geo-statistics.

concentration of mineralpoint of next experimentconfidence intervals
interpolation

geographical location
27

Kriging using 101 ab-initio LTC data

First prediction was made using N0（=5） LTC data and GPR.

Use of 34 elemental descriptors on top of V and ρ is found to be effective
to overcome an outlier problem.

28

Ranking of LTC for 54,779 compounds in ICSD library“Virtual screening”

Z‐score∗∗log κ⁄∗The higher Z-score, the lower predicted LTC !

29

Top 10 lowest LTC compounds among 54,779
Virtual screening of 54,779 compounds in MPD library
ab initio LTC

30

Lattice Thermal Conductivity (LTC)

Newly discovered !!

31

Thermoelectric materials
Essential for utilizing otherwise waste heat.

PowerLow T
Electric current

Heat fluxp-typen-typeElectric currentFigure ofMerit

Electric current

High T∶ Seebeck coefficient: electrical conductivity: thermal conductivity

32

Top 10 lowest LTC compounds among 54,779
Virtual screening of 54,779 compounds in MPD library
ab initio LTC

33

Newly discovered candidates for thermoelectrics
with low LTC of < 0.5 W/mK (@300 K)
and narrow band gap of < 1 eV.

A. Seko, A. Togo, H. Hayashi, K. Tsuda, L. Chaput, and IT PRL 115, 205901 (2015)34

Fin