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Accelerated Materials Discovery & Characterization with Classical, Quantum and Machine learning approaches
1. Accelerated Materials Discovery &
Characterization with Classical, Quantum and
Machine learning approaches
Kamal Choudhary
National Institute of Standards and Technology, Maryland, USA
IIT-BHU, November 19, 2018
1
Web: https://jarvis.nist.gov
2. Acknowledgement and Collaboration
2
F. Tavazza
(NIST)
C. Campbell
(NIST)
K. Garrity
(NIST)
A. Reid
(NIST)
D. Wheeler
(NIST)
A. Biacchi
(NIST)
F. Congo
(NIST)
J. Warren
(NIST)
C. Becker
(NIST)
E. Reed
(Stanford)
A. Agarwal
(Northwestern)
T. Liang
(Penn state)
M. Bercx
(Antwerp)
B. DeCost
(NIST)
3. Outline
⢠Motivation
⢠Few basics
⢠JARVIS-FF: Evaluation of FF:
⢠Energetics and elastic properties
⢠Surface energies
⢠Vacancy formation energies
⢠JARVIS-DFT: Discovery & characterization:
⢠Low-dimensional materials (2D, 1D, 0D)
⢠Topological materials
⢠Efficient solar-cell materials
⢠High-performance thermoelectric materials
⢠Flexible and negative Poisson ratio materials
⢠JARVIS-ML: ML training
⢠Website/github demo
3
Navigate to:
https://jarvis.nist.gov
5. Few basics
⢠Materials Science is all about: Structure-Property-Performance relationship and minimization of
free-energy
⢠Computationally: Structure = lattice constants (a,b,c), angles (alpha, beta, gamma) and basis
vectors ([Si,0, 0,0],[Si,0.5,0.0,0.5],âŚ..)
⢠To calculate property: classical physics (e.g. classical force-fields), quantum physics (e.g. density
functional theory)
⢠MGI motivated current computational databases: Materials-project (MP), AFLOW, OQMD
ICSD
database
(with
experiment
al lattice
constant)
AFLOW
OQMD
PBE
Materials Project MIT, LBNL
(67,486 materials)
Duke University
(1,640,245 materials)
Northwestern university
(471,857 materials)+SQS
Others: AIIDA, MaterialWeb, NREL-MatDB etc.
5
6. Classical force-fields
⢠Coulomb potential
⢠Lennard-Jones potential
⢠Morse-potential
⢠Stilinger-Weber potential
⢠EAM and MEAM potential
⢠Bond-order/Tersoff/Brenner
⢠Fixed charge potentials: Coulomb-Buckingham
⢠Other FFs: ReaxFF, COMB, AMBER, CHARMM, OPLS etc.
6
( ) ( )( )
12
21
2211 ,
rr
qkq
rqrqV ď˛ď˛
ď˛ď˛
â
= One parameter to fit/optimize
Repulsive and attractive terms, Two parameters to fit
These potentials lack angular information hence not able to capture elastic constants well
Uses electron density, for metallic systems
These potentials lack charge information
Uses angle but transferability problem
Uses bond information, for covalent systems
Berni Alder
iii amF = , VF ii âď= , 2
2
dt
rd
m
dr
dV i
i
i
=â
8. Energetics and elastic properties
Nature:Scientific Data 4, 160125 (2017)
⢠Comparison of DFT convex hull and bulk modulus
⢠Some FFs are not fit for high energy phases and elastic
properties
8
9. Surface energies and vacancy formation
Accepted J. Phys. Cond. Matt.
Comparison of elemental surface and defect formation energies
9
10. Density Functional Theory
⢠Classical Newtonâs laws not applicable for electrons (very fast, very tiny);
⢠SchrÜdinger equation: mathematical equation that describes the evolution
over time of a physical system in which quantum effects, such as waveâparticle duality,
are significant (such as electrons)
⢠SchrĂśdinger equation of a fictitious system (the "KohnâSham system") of non-interacting particles (typically electrons) that
generate the same density as any given system of interacting particles
⢠Uses density vs wavefunction quantity
⢠Different functionals: LDA, GGA (PBE, PW91), HSE06 etc.
⢠LDA: developed for homogenous systems (Thomas-Fermi model), such as metals
⢠GGA: uses density gradient information on top of GGA
⢠vdW-DF: uses exchange from GGA, correlation from LDA, quantum-Monte-Carlo
based non-local corrections, optB88vdW used here mainly
https://en.wikipedia.org/wiki/Classical_mechanics
http://www.psi-k.org/Update3.shtml
http://www.physlink.com/Education/AskExperts/ae329.cfm
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m
iiiEff ďšďš =ďş
ďť
ďš
ďŞ
ďŤ
ďŠ
+ďâ 2
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XCeeNeEff VVVTV +++=ďšďš EH =
Walter Kohn
Exchange-correlation
Hohenberg, Pierre; Walter Kohn (1964). "Inhomogeneous electron gas". Physical Review. 136 (3B): B864âB871
( ) 0
8
2
2
2
2
=â+
ďś
ďś
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VE
h
m
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P o s i t i o n
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derivative wrt X
Schrodinger
Wave-function
Position Energy Potential Energy
10
11. Discovery of 2D (low-D) materials
11
ICSD
ICSDPBE
c
cc â
=ď¤
If the error is more than 5% > 1500 materials
Using lattice-constant
error to discover low-D
materials
Nature:Scientific Reports 7, 5179 (2017)
Physical Review B 98 (1), 014107 (2018)
13. Topological materials
⢠Metals, Semiconductors, Insulators
⢠New class of materials: Topologically non-trivial materials
⢠Topology: the study of geometric properties and spatial relations unaffected by the continuous
change of shape or size of figures
⢠TIs: Bulk insulator, robust conducting surface states,
absence of backscattering
⢠Application: Topological supercomputing due to reduced
scattering
http://www.phys.virginia.edu/Files/fetch.asp?EXT=Seminars:2606:SlideShow13
https://www.nature.com/articles/466323a
https://en.wikipedia.org/wiki/TopologyEmail: kamal.choudhary@nist.gov
No tearing apart/joining, only stretching and bending
14. Discovery of topological materials
14
Using DFT wavefunctions w/o spin-orbit coupling to discover topological materials
https://arxiv.org/abs/1810.10640
Surface states are topologically protected, aspect for Quantum computing
15. Discovery of topological materials
15
Wannier function, band-crossings, inversion, ARPES Periodic table trends
https://arxiv.org/abs/1810.10640
⢠>1699 high-spillage materials identified
⢠Further screened with close to zero indirect bandgap [ÎEn] ( to avoid trivial metallic cases)
⢠278 Wannier calculations
PbS LiBiS2
KHgAs GaSb
16. Discovery of solar cell materials
16
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20
22
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ďĄď˘
++â
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= ďĽ
Frequency dependent dielectric function with TBmBJ Nature:Scientific Data 5, 180082 (2018)
One of the most important field of research for sustainable eco-friendly energy requirement
17. Éł =
đ đđđĄ
đđđđ
=
đ˝đ đ â đ˝0 đ
đđ
đžđ â 1 đ
1000
Spectroscopic Limited Maximum Efficiency (SLME)
- Zunger group (NREL)
Paper in preparation
>1500 screened materials
Discovery of solar cell materials
18. Discovery of thermoelectric materials
18
>2000 high-power factor materials
Constant relaxation time approximation, BTE solver Paper in preparation
For waste-heat
management
19. Discovery of negative Poisson and flexible materials
Physical Review B 98 (1), 014107 (2018)
19
Dimensionality dependent elastic properties
PbS (â0.5, Cmcm, JVASP-28369), Al (â6.2, Imâ3m, JVASP-25408), CSi2 (â0.13, P6/mmm,
JVASP-16869), YbF3 (â0.06, Pnma, JVASP-14313), SiO2 (â0.03, Pna21, JVASP-22571)
20. 2D-Heterostructure design with elastic constant
and work-function data
In preparation 20
⢠Lattice mismatch and elastic tensor to predict elastic energy of the interface
⢠Work-function/band-alignment match
Zur et al., Journal of Applied Physics 55, 378 (1984)
21. Finding the right features/descriptors: Machine
learning
21
1557 descriptors/features for one material
Gradient boosting decision tree algorithm
⢠Arithmetic operations (mean, sum, std. deviationâŚ) of
electronegativity, atomic radii, heat of fusion,âŚ.
(example: Electronegativity of Mo+Mo+S+S+S+S)/6 = 0.15
⢠Atomic bond distance based descriptors
⢠Angle based descriptors
Physical Review Materials 2, 083801 (2018)
22. Visualizing multi-dimensional data with t-SNE
22
⢠Converts similarities between data points to joint probabilities
⢠Visulaization with t-SNE for ~25000 materials
http://holoviews.org/
http://scikit-learn.org/stable/modules/generated/sklearn.manifold.TSNE.html
23. Regression models: formation energy and bandgap
model
23
Learning curve, 1 and 5-fold CV plots
Total 14 models trained
Physical Review Materials 2, 083801 (2018)
24. Explainability: feature importance
24
⢠Chemical features most important followed by RDF and NN
⢠Incrementally adding structural features decreases MAE
Physical Review Materials 2, 083801 (2018)
https://www.darpa.mil/program/explainable-artificial-intelligence
25. Search for new materials: Genetic algorithm with ML
25
⢠MoS2, WS2 indeed stable as in DFT and experiments
⢠Need further verification foor low-lying energy structures with DFT
⢠New way of validating ML model for materials
Physical Review Materials 2, 083801 (2018)
26. 2D materials screening: flexible electronics
applications
26
⢠~5000 2D materials predicted
⢠Requires expensive DFT calculations for predicting properties such as bandgap, exfoliation energy etc.
⢠Use of ML drops down the time to a few seconds
⢠Using this technique we identified new 2D materials such as CuI, InS etc.
⢠Validated using DFT
27. Exploring the github and webpages
27
Continuous integration, various modules, notebooks etc.
Example: https://www.ctcms.nist.gov/~knc6/jsmol/JVASP-1067.html
Exploring material properties
Github:
https://github.com/usnistgov/jarvis
Web: https://jarvis.nist.gov
28. Future work
28
⢠Integration of high-throughput experiments
⢠Natural language processing
⢠Benchmark experimental database
⢠Ferroelectric and ferromagnetic materials discovery
⢠Integration of other computation techniques: FEM, TB etc.
⢠Voice-recognition data query in addition to web-search
⢠Visualization of multi-dimensional data
⢠Uncertainty in ML algorithm predictions
⢠Multi-output regressionâŚ
29. JARVIS-DFT
29
JARVIS-FF JARVIS-ML
( )rVmaF âď==
( ) ( ) ( ) ( )
2
2
2
Eff i i iV r r E r r
m
ďš ďš
ďŠ ďš
â ď + =ďŞ ďş
ďŤ ďť
XCeeNeEff VVVTV +++=
ďšďš EH =
⢠Solve Newtonâs equation for atomic positions
⢠Approximations for V (force-fields):
EAM, EIM, MEAM, AIREBO, REAXFF, COMB, COMB3,
TERSOFF, SW etc.
⢠Contains:
Automated LAMMPS based force-field calculations on DFT
geometries. Some of the properties included in JARVIS-FF are
energetics, elastic constants, surface energies, defect formations
energies and phonon frequencies of materials
⢠Time: Takes years to fit FFs, relatively quick calculations
⢠Website: https://www.ctcms.nist.gov/~knc6/periodic.html
⢠Publications:
⢠Nature:Scientific Data 4, 160125 (2017)
⢠J. Phys. Cond. Matt.
Force-field (classical) Density-functional theory (quantum) Machine learning (data-driven)
⢠Solve SchrÜdinger equation for electrons
⢠>30,000 materials data (3D, 2D, 1D, 0D)
⢠Contains:
Formation energy, exfoliation energy, diffraction pattern, radial
distribution function, band-structure (SOC/Non-SOC), density
of states, carrier effective mass, temperature and carrier
concentration dependent thermoelectric properties, elastic
constants and gamma-point phonons
⢠Time: 5000 cores for last 4 years
⢠Website: https://www.ctcms.nist.gov/~knc6/JVASP.html
⢠Publications:
⢠Nature:Scientific Reports 7, 5179 (2017)
⢠Nature:Scientific Data 5, 180082 (2018)
⢠Phys. Rev. B 98, 014107 (2018)
⢠Drawing the line, dimensionality reduction, curve-
fitting?
⢠Neural nets, decision trees, fuzzy-logic etc.
⢠Uses gradient boosting decision tree
⢠Contains:
Machine learning prediction tools, trained on JARVIS-
DFT data.
Some of the ML-predictions focus on energetics, heat of
formation, GGA/METAGGA bandgaps, bulk and shear
modulus, exfoliation energy, refractive index, magnetic
moment, carrier effective masses
⢠Time: Much easier and faster to train
⢠Website: https://www.ctcms.nist.gov/jarvisml/
⢠Publication:
⢠Phys. Rev. Materials 2, 08380 (2018)
SchrĂśdinger's cat
Web: https://jarvis.nist.govEmail: knc6@nist.gov or
kamal.choudhary@nist.gov
Github:
https://github.com/usnistgov/jarvis