材料設計における規則性の シミュレーション - umekkii1 sim colloquium, july 4,...
TRANSCRIPT
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SIM Colloquium, July 4, 20031
•• データベースの方法
•• 第一原理電子論の方法第一原理電子論の方法
シミュレーションコロキウム 2003年7月4日
材料設計における規則性のシミュレーション
システム量子工学専攻 岩田研 助教授 陳 迎
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SIM Colloquium, July 4, 20032
• 科学技術データと社会
科学技術データを私財ではなく人類全体の公共財とするための基礎的研究。異分野間の連携を考えたメタデータ、メタ知識、インターフェイスとインタラクション、知識の再構築と獲得といった情報論的な課題の他に、知的所有権、情報価値、情報戦略、情報流通等に関する原則・規範と制度化、さらには情報格差の取り扱い、克服までも視野に入れた基盤科学としてのデータサイエンス。以下の人工物と材料を実践的研究の対象としている。
• 人間と人工物
人間系を基軸に人工物群全体を視野にとらえた新しいエンジニアリング。環境、ランドスケープ、原発、ゴミ処理プラントの合意形成、人工物を介した異分野間の情報共有、世代間の技術継承、抽象化された知識と経験(身体性)との相補性、ニーズとシーズの相補性、情報環境とマーケッテング。
• 人間と材料
物質・材料データベースを活用したデータ駆動型の設計手法の構築。複雑システムのモデリングにおいては個々の事実の具体的かつ徹底的な記述と多様なレベルでの抽象化と相互比較・分析、類推が有効であることを示し、また、優れたインターフェイスの開発により、比喩的には「手が考える」状態を実現しつつある。
岩田研究室岩田研究室 研究内容研究内容
→ 材料設計に関する理論的研究
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SIM Colloquium, July 4, 20033
I. Introduction
Periodic Table of the Elements
UnaryBinaryTernaryQuaternary…Multinary
私達の世界の物質・材料は約110種類の元素による無限の組み合わせでできています.
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SIM Colloquium, July 4, 20034
I. Introduction Substance, Material
• State 物質の状態Solid, Liquid, Gas, …
• Composition (element A, B, C, …)Unary: ABinary: A-B
eg. AB, AB2, A2B3, Ternary: A-B-C
eg. ABC2, AB2C3
• Alloy CompoundSolid solutionInsolubility
… Multinary
成分
純物質
二元系
三元系
多元系
合金
化合物
固溶体
Phase Diagram
Liquid
Compound
Al Atomic Percent of Ca Ca
Tem
pera
ture
ºC
状態図
1078ºC
842ºC
Al3
Ca8
Al4
Ca
660.45ºC
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SIM Colloquium, July 4, 20035
I. Introduction Intrinsic Property
Chemical propertyMechanical propertyThermal and thermodynamic propertyElectronic and electrical propertyOptical propertyFerroelectric propertyMagnetic property…
• Properties of material
• Properties of elementDensityAtomic weightAtomic radius…
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SIM Colloquium, July 4, 20036
I. Introduction Crystal Structure
There are more than 3,000 known crystal structures
fccsc bcc
…
PbSの天然結晶塩化ナトリウム構造をもつ
塩化ナトリウム結晶模型
塩化ナトリウム単位格子
Minimum repeated unit:
Unit call
結晶構造
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SIM Colloquium, July 4, 20037
I. Introduction
Same element in Various structures → Various properties
eg. Carbon
C60 C-tubeDiamond
High pressureState高圧相
Graphite
normal state定常相
Nano scale
…
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SIM Colloquium, July 4, 20038
I. Introduction
eg. Cohesive Energy (eV/atom)
Periodic Table of the Elements
Periodicity of elemental property
凝集エネルギー
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SIM Colloquium, July 4, 20039
I. Introduction Regularity
Regularities
• Are compounds formed or not when 2 elements meet?• What compositions are realized in a former system?• What structures are formed for a compound?• What is the physical property for a compound in certain
structure?
Atomic constitutionAtomic constitution
Structure of MaterialsStructure of Materials Properties of MaterialsProperties of Materials
規則性
組成
構造 物性
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SIM Colloquium, July 4, 200310
I. Introduction 材料設計に関する理論的研究
UnaryBinaryTernaryQuaternary…Multinary
Databases / Data mining → Discovery
Simulation
First principles approach → Origin
Periodic Table of the Elements
Regularity
Experiment
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SIM Colloquium, July 4, 200311
PAULING FILE Binaries Edition
• Pauling File Project
1995 ~ Japan Science and Technology Co. (JST)Material Phases Data System (MPDS) The University of Tokyo
• Data Source~ 150,000 original publications> 1,000 scientific journals since 1900
• ScopeAll non-organic solid states materialsFour types of data:
StructureDiffractionConstitutionPhysical propertyData
28,300 structure data28,300 diffraction data8,000 Phase diagrams17,300 property entries
Discovery Took
Binaries Edition: CD-Rom
II. Data Driven Approach
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SIM Colloquium, July 4, 200312
• Postulation
Property of MaterialsElemental Property Parameters (EPPs)
Expression
• Purpose
To order the huge amount of data within plots so that thematerials with same structure type/properties are clustered together , to systematize the relationship between properties
or between structure and property.
II. Data Driven Approach Mapping
• Two key points in mappingCharacterization: To find optimal coordinatesClassification: To define meaning of domains
データ駆動型の設計手法
軸の取り方
領域の定義
仮想
目的
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SIM Colloquium, July 4, 200313
Structure Map - D. Pettifor’s Map (1985)
MN(A)
MN
(B)
University of Oxford
David Pettifor
II. Data Driven Approach
2D構造マップ
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SIM Colloquium, July 4, 200314
Quantum Structure Diagram (QSD) - P. Villars’ Map (1983)
…
QSD Our Calculation
1.01.52.02.53.03.5
Nv
∆χ
∆R{{Section 3
Section 2
Section 1
s-s (IA-IA)s-s (IA-IIA)s-p (IA-IIIA)s-p (IIA-IIIA)s-p (IA-VA)p-d (IIIA-IIIB)
/ p-d (IIIA-IIB)
{
(∆E)
(d)
x: difference of Zunger’s radiiy: difference of M-B elentronegativityz: sum of valence electrons number
P. Villars
MPDS, Switzerland
II. Data Driven Approach
3D構造マップ
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SIM Colloquium, July 4, 200315
Finding Regularity by EPP + AET
2,300 Conventional Structures
2,300 Conventional Structures
~30 Atomic Environment Types
~30 Atomic Environment Types
56 Element Property Parameters
56 Element Property Parameters
2-3 Optimal EPP Expressions
2-3 Optimal EPP Expressions
Distribution, Patterns, …?
II. Data Driven Approach
規則性探索の手順
原子配置環境タイプ
元素特性パラメータ 最適元素特性パラメータ
古典的結晶構造
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SIM Colloquium, July 4, 200316
Element Property Parameters (EPPs)
• 6 most distinct EPP groupsAtomic numberGroup numberMendeleev numberCohesion energyElectrochemical factorSize
• OperationsSum EP(A)+EP(B)Difference EP(A)-EP(B)Product EP(A)*EP(B)Ratio EP(A)/EP(B) Maximum Max(EP(A),EP(B))Minimum Min(EP(A),EP(B))
• EPPEP(tot) = EP(A) op EP(B)
• Example of EPsAtomic numberMendeleev Number
(D. G. Pettifor, 1983, …)Atomic radiiMelting pointElectronegativity
Mendeleev Number
……
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SIM Colloquium, July 4, 200317
Atomic Environment Type (AET)
CuMg: CsCl-type AET: CN148 1st n.n. + 6 2nd n.n.
Max Gap
• AET Types of a Structure Single, Double, Triple, …
Maximum-gap RuleMaximum-convex-volume Rule
• Rules of Constructing AET
• Concept of AET Based on Coordinates Polyhedron
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SIM Colloquium, July 4, 200318
Finding Regularity by EPP + AET
2,300 Conventional Structures
2,300 Conventional Structures
~30 Atomic Environment Types
~30 Atomic Environment Types
56 Element Property Parameters
56 Element Property Parameters
2-3 Optimal EPP Expressions
2-3 Optimal EPP Expressions
Distribution, Patterns, …?
II. Data Driven Approach
規則性探索の手順
原子配置環境タイプ
元素特性パラメータ 最適元素特性パラメータ
古典的結晶構造
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SIM Colloquium, July 4, 200319
Regularity in Binaries
Periodic Table of the Elements
2D Formation Map
CoordinatesMN(A) vs. MN(B)
Very few compounds in range
between MN
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SIM Colloquium, July 4, 200320
Regularity in Binaries
Magnesium - X
Constitution 周期律表型組成マップ
II. Data Driven Approach
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SIM Colloquium, July 4, 200321
MN(A) vs. MN(B)
Density (Mg/cm3) 0 5 10 15 20Density [Mg・ m-3]0
1000
2000
3000
4000
Tm
[K]
cluster1cluster2cluster3cluster4
Density vs. Melting pointClustering
Physical Properties
Regularity in BinariesII. Data Driven Approach
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SIM Colloquium, July 4, 200322
Application of Structure map
χ∆R∆vN =4.2-4.75.6-5.7
vN
χ∆
R∆
Superconductors
Quasicrystalχ∆
MgB2
II. Data Driven Approach
x: difference of Zunger’s radiiy: difference of M-B elentronegativityz: sum of valence electrons number
Application
準結晶
超伝導
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SIM Colloquium, July 4, 200323
• Can not provide insight into the microscopic mechanism
• Limited experimental data leads to uncompleted separation of different domains
Combining First Principles Approaches
II. Data Driven Approach Limitation
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SIM Colloquium, July 4, 200324
III. First Principles Approach
Physical Model
Many-body (Ions+Electrons) problem
Many-electron problem
One-electron problem
Born-Oppenheimer (Adiabatic) Approximation
One electron Approximation
多体問題 ~1023
多電子問題
一電子問題
一電子近似
断熱近似
第一原理電子論の方法
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SIM Colloquium, July 4, 200325
Solution of One-electron Schrödinger Equation
Typical wayExpanding one-electron wave function with a set of
basis function to construct the Secular equation
χik (
r r ) = cn (i,
n∑
r k )φ(
r k n ,
r r )
det (
r k 2 − ε )δ r k , r k ' + φ(
r k 'n ,
r r )V(
r r )φ* (
r k n ,
r r )∫ d
r r = 0
First principles approach: without using empirical parameters(Semi-)Empirical approach: using empirical parameters
III. First Principles Approach
ε = εi (r k )
一電子シュレーディンガー方程式
第一原理方法
(半)経験的方法
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SIM Colloquium, July 4, 200326
III. First Principles Approach
Self-Consistant Field (SCF) Approach
SecularequationSecular
equationNew
densityNew
densityNew
potentialNew
potentialInitial
potentialInitial
potential
Initial densityInitial
density
Same as former
potential
YesNoConvergentproperties
Convergentproperties
自己無撞着
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SIM Colloquium, July 4, 200327
Electronic Band Structures ε = εi (r k )
Total energy Density of States Energy Band Charge density
fcchcp
bcc
Cu:
Face Center Cubic(fcc)
Body Center Cubic(bcc)
Hexagonal(hcp)
Ground state
fcc
III. First Principles Approach Results
全エネルギー 電子密度 エネルギーバンド 電荷密度
電子エネルギーバンド構造
体心立方面心立方 六方晶
基底状態
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SIM Colloquium, July 4, 200328
Application
Atomestic Simulation of Materials
• To explain microscopic mechanism of experiments. … 解明
• To predict unknown substance and unknown properties. … 予測
III. First Principles Approach
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SIM Colloquium, July 4, 200329
What Understand
Energy gap: Insulator, Semiconductor, Metal
C-diamond Si Fe
E band
DOS
EF
EF
III. First Principles Approach
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SIM Colloquium, July 4, 200330
Application
Prediction of new super hard substance: cubic-C3N4Bulk modulus: higher than diamond
D. M. Teter, et al., Science, 271 (1996), 53
Experiment: 1998Spinel structure
III. First Principles Approach
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SIM Colloquium, July 4, 200331
Application
Nano simulation: Band alignment for SiO2/Si interfaceT. Ohno, et al., NIMS, 2003
III. First Principles Approach
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SIM Colloquium, July 4, 200332
Application
Inverse band structure problemA. Zunger, et al., Nature, 402 (1999), 60
Conventional problemAtomic configuration → Electronic structure
Electronic structure → Atomic configurationMax-gap configurations of AlxGa1-xAs alloys for different Al conc. x
Inverse problem
(GaAs)2(AlAs)1(GaAs)4(AlAs)1 (GaAs)2(AlAs)2 (GaAs)1(AlAs)3
Ga
Al
As
National Renewable Energy Laboratory
USA
III. First Principles Approach
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SIM Colloquium, July 4, 200333
Phase Diagram
Liquid Compound
Temperature - Concentration Temperature - Pressure
Fe
bcc hcp
fcc
bcc
Finite TemperatureIII. First Principles Approach
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SIM Colloquium, July 4, 200334
= + + + + + …
Free energy: STEg ⋅−=
Total energy EntropyCluster Variation
(CVM)Cluster Expension
(CEM)
Finite TemperatureIII. First Principles Approach
First Principles total energy: Ground state (0K)
First Principles + Statistical MechanicsHow to deal with finite temperature:
有限温度
統計力学第一原理電子論
クラスター変分法クラスター展開法
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SIM Colloquium, July 4, 200335
Periodic Table of the Elements
Fe-Pd
L10 L12
Fe-PtL10 L12
L12
L12
Fe-Ni
Finite TemperatureIII. First Principles Approach
First Principles Study on Phase Stability and Equilibriafor Fe-Ni, -Pd and -Pt Systems
Y. Chen, T. Mohri, S. IwataJ. Phys., Mater. Trans., Calphad, 2002
An example
L10 L12
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SIM Colloquium, July 4, 200336
IV. Our Present Research
1) Data Miningによる物質世界の規則性の探求と材料設計:
「Pauling File」という膨大な物質・材料の基礎データを揃えた
データベースを基本に据え、操作性の高いインターフェース
「Discovery Space」の上でデータの俯瞰・再編と複雑な関係の抽
出という一連の操作をしながら、データ群の背後に潜む規則性を
発見し、その延長線上に、この世界には未だ存在しない未知の新
物質・新材料を設計・開発する研究です。
2) 第一原理電子論計算による物質世界の規則性の解明と材料設計:
第一原理電子論計算と、統計力学のクラスター変分法や熱力学の
CALPHAD法を組み合わせることにより、与えられた物質・材料の構
造安定性や相平衡状態図を予測し、相安定性の起源や相変態のダ
イナミクスを明らかにした上で、非平衡・準安定平衡材料の設計
を目指しています。
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SIM Colloquium, July 4, 200337
IV. Our Present Research
• Extending Approach
• Status of Materials Research
60% 5%
Binary Ternary Quaternary