From Quanta to the Continuum: Opportunities for Mesoscale Science

1. From Quanta to the Continuum: Opportunities for Mesoscale Science George Crabtree John Sarrao Co-chairs BESAC subcommittee on Mesoscale Science Outline Mesoscale architectures and hallmarks Opportunities for mesoscale science New tools, facility modes and techniques Cross-specialty workforce by multi-mentoring Perspective science.energy.gov/bes/news-and-resources/reports/basic-research-needs/ www.meso2012.com/

2. The BESAC Charge on Mesoscale Science • Excerpts from Dr. Brinkman’s charge letter of February 14, 2011: • A central theme of these reports is the importance of atomic and molecular scale understanding of how nature works and how this relates to advancing the frontiers of science and innovation. I would now like BESAC to extend this work by addressing the research agenda for mesoscale science, the regime where classical, microscale science and nanoscale science meet. I see two parts to this new study: • 1. Identify mesoscale science directions that are most promising for advancing the Department’s energy mission. • 2. Identify how current and future BES facilities can impact mesoscale science. • This study could prompt a national discussion of mesoscale science at the level heard during the initial formulation of the National Nanotechnology Initiative a decade ago. Report due early Fall 2012

3. The BESAC Meso Subcommittee John Hemminger, Irvine, BESAC chair William Barletta, MIT, BESAC Gordon Brown, Stanford, BESAC Roger French, CWRU, BESAC Laura Greene, UIUC, BESAC Bruce Kay, PNNL, BESAC Mark Ratner, Northwestern, BESAC John Spence, Arizona, BESAC Doug Tobias, Irvine, BESAC John Tranquada, Brookhaven, BESAC John Sarrao, LANL, co-chair George Crabtree, ANL & UIC, BESAC, co-chair Paul Alivisatos, LBNL Frank Bates, Minnesota Marc Kastner, MIT Jennifer Lewis, UIUC Tony Rollett, CMU Gary Rubloff, Maryland

4. Mesoscale Architectures dynamics structure 20 nm 50 nm Polymer science Supramolecular chemistry nanocrystal arrays properties multilayers 100 µm phase separation polarization domains fossil fuels teflon CH4 methane CF4 carbon tetrafluoride chemical bonds periodic lattices atoms

5. Hallmarks of Mesoscale Phenomena Diminished atomic granularity The position and presence of a given atom has decreasing impact n=3 n2 h2 8ma2 E n=2 E = Degree of energy quantization n=1 a a ΔE = 3h2/8ma2 0.1 nm 106 K 1 nm 104K 10 nm 102 K 100 nm 1 K 1000 nm 0.01 K  room temperature Increasing length scale promotes interactions with environment, greater complexity, new phenomena

6. Hallmarks of Mesoscale Phenomena Interacting degrees of freedom Developed collective behavior e.g., charge screening Length:34µm 0.4 2.8 V 0.2 0.0 Height (µm) -0.2 Cantilever clamping point -0.4 -0.6 0 V -0.8 0 0.02 0.04 charge compensation length Length (mm) Baeket al, Science 334, 958 (2011) piezoelectricity metals semiconductors electrolytes electrons electrons / holes ions Thomas-Fermi Debye Debye-Huckel 0.1 nm 1-1000 nm 0.1 – 100 nm electrons+phonons=superconductivity ferromagnetism+ferroelectricity=multiferroics photon+semiconductor=electron . . .

7. Hallmarks of Mesoscale Phenomena Heterogeneity in structure and dynamics Defects, fluctuations, statistical variation nanoparticles: single grain, single domain small molecules perfect structure large assemblies imperfect structure basis for genetic mutation and evolution meso and larger particles heterogeneous grain and domain structures • In mesoscale and larger crystals • defects profoundly affect • • electrical conductivity • • mechanical response • • heat transport composite parts that cooperate degrees of freedom interact across interface

8. Examples of Mesoscale Phenomena O2 H2O Giant Magnetoresistance • Hallmarks • • Heterogeneity • • Interacting degrees of freedom • charge and spin • • Defects at surface H+ CoFe MgO CoFe H2O OK H2 Birth of spintronics Permanently changed the landscape of computer memory Photo-electro-chemical Water Splitting • • interacting degrees of freedom • photonic, electronic, chemical • • heterogeneous - composite parts • • defects, fluctuations, statistical variation • • atoms and quantized energies • • continuous matter and energy

9. Meso Opportunity: Mastering Defect Mesostructure and its Evolution Crack Propagation Deformation 3D Coherent Imaging Crack Initiation Failure x-ray tomography New probes enable imaging of damage initiation and evolution at the mesoscale 9

10. Opportunity: Strongly correlated electrons Kondo spin compensation cloud contacts for transport measurements confinement length R.M. Potok et al., Nature 446, 167-171 (2007). Quantum Dot local moment ~ 1000 electrons compensating conduction electrons Unfold the statics and dynamics of partial Kondo spin compensation spin compensation length Opportunity mesoscale confinement of strongly correlated electrons • charge screening • Mott-Hubbard localization • Kondo compensation Cuprate superconductors six strongly correlated electron phases correlation grows toward left Varma, Nature 468, 184 (2010)

11. Opportunity: Reactive Flow in Porous Media Groundwater dynamics, fossil fuel formation and extraction, shale fracking, carbon sequestration Fracking challenges • fluid flow in mesoporousrock • fracture dynamics and evolution • contamination of water, air • initial rush of gas / sharp decline • only 15% of shale gas recovered Separation membranes polymers metal organic frameworks reverse osmosis chemical functionalization carbon dioxide capture water purification chemical separation

12. Opportunity: Directing Assembly of Hierarchical Functional Materials Elements of Assembly compositional structural functional unit connecting functional units architectural connecting sequential steps temporal many interacting degrees of freedom Integration of disparate materials classes by “top down” and “bottom up” approaches is the underpinning focus of directed mesoscale assembly 12

13. Opportunity: Directed Assembly of Battery Electrodes Self-Assembly Silicon coated carbon fibers for battery electrodes 100 nm Magasinski et al, Nature Materials 9, 353 (2010) Biology is proof of concept and inspiration for functional self assembly Little wasted material, organized instead of random mesoscale structure Now: create complex structures Opportunity: impart functionality Self-assembled structures with the complexity and functionality of biology using earth-abundant inorganic materials

14. Opportunity: Manufacturing at the Mesoscale Now • Manufacturing by assembly of macroscale components via macroscale interconnects • Components made by top down fabrication, removing unwanted material to create functional object • Lithographic fab lines, auto parts, . . . Ultralight metallic microlattices Schaedler et al, Science 334, 962 (2011) • Future • • Integrate bottom up self-assembly with top down design and fabrication • • Retain top down design for targeted functionality • • Employ bottom up self-assembly to utilize starting materials effectively • • Replace macroscale interconnects with mesoscale interfaces • Eliminate wires, hydraulic and chemical flow channels, mechanical linkages • • Less waste, lighter weight, higher efficiency, longer life, more competitive

15. Tools, Facilities and Techniques Meso space is large and complex Everything is connected to everything else • Integration of computation, characterization and synthesis • computation is needed to • •explore phase space of mesomaterials • • predict outcomes of self-assembly • • test designs and ideas before implementation • • coordinate multi-modal measurements • • manage “meso informatics” • Computer hardware is up to the job • Moore’s Law in throughput - factor of 1000/decade • New science formulations and applications needed • to bring computation to full potential

16. Exciting new sources (e.g., LCLS, NSLS-II, SNS) are available, but need to advance optics, detectors, environments, and data handling • New methods to watch multi-d defect evolution & tracking • In situ, in operando measurements • Long duration measurements Simultaneous diffraction, imaging and spectroscopy x-ray tomography Time-correlated probes of local structure, composition, excitation Data mining strategies 3 dimensional, in situ, multi-modal measurement 3D Coherent Imaging 16

17. Theory and simulation need to connect models across scales AND incorporate emergent phenomena to realize functionality by design years days sec macro ms Well-documented and curated community codes is a key gap time scale µs meso Mori-Tanaka, Halpin-Tsai, Lattice Spring, Finite Element atomic molecular nano ns ps Lattice Boltzmann TDGL, DDFT, DFT MD, MC,DMFT fs mm µm m nm length scale Computational materials challenges include experimental validation 17

18. Workforce Training to Tap the MesoOpportunity • Meso frontier is interdisciplinary and inter-specialty • Need researchers to move across disciplinary and specialty boundaries • Need integrated research teams to address multifaceted challenges • Foster and grow science of mesoscale synthesis • Heterogeneous systems with interacting composite parts • Multi-modal measurements • Enhanced partnering with instrument scientists at large scale facilities • Seamless integration of theory and simulation with synthesis and characterization • Translation to community codes • Multi-mentoring by two or more advisors to cross disciplines and specialties • Multilingual graduate students and early career scientists • Future mesoscale scientists will fuel broader manufacturing and innovation workforce 18

19. Meso: a Constructionist Approach to Science Constructionist Reductionist built environment fracture cracks rocks geoformations fossil fuels plants animals vortices mean free path defect aggregation work hardening sedimentary rocks cells life Cooper pairs Hallmarks of mesoscale phenomena  Hieraarchialmesoscalearlchitectures electron-phonon resistivity structural defects plastics membranes colloids superconductors magnetics domains, hysteresis mechanics phonons electronics insulators - metals polymers solutions periodic lattices chemical bonds atoms

20. Perspective on Mesoscience • A new frontier, where quanta meet the continuum • Six hallmarks of meso phenomena • atomic granularity; energy quantization; collective behavior; • interacting degrees of freedom; defects, fluctuations and statistical variation; • heterogeneity of structure and dynamics • Hierarchy of mesoscale architectures • based on chemical bonds and periodic lattices • Integration of disciplines and specialties • especially computation with synthesis and characterization • Multimodal tools for in situ spatial and dynamic resolution • Cross-boundary workforce trained by multiple mentors • Constructionist science • use nano tools and knowledge to create new meso phenomena a discovery laboratory for finding new phenomena a self-assembly foundry for creating new functional systems a design engine for new technologies