| NSF Org: |
DMR Division Of Materials Research |
| Recipient: |
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| Initial Amendment Date: | August 16, 2011 |
| Latest Amendment Date: | September 12, 2013 |
| Award Number: | 1122594 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Daniele Finotello
DMR Division Of Materials Research MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | September 1, 2011 |
| End Date: | August 31, 2015 (Estimated) |
| Total Intended Award Amount: | $3,000,000.00 |
| Total Awarded Amount to Date: | $3,120,000.00 |
| Funds Obligated to Date: |
FY 2012 = $60,000.00 FY 2013 = $1,060,000.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
615 W 131ST ST NEW YORK NY US 10027-7922 (212)854-6851 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
615 W 131ST ST NEW YORK NY US 10027-7922 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
OFFICE OF MULTIDISCIPLINARY AC, Materials Teams |
| Primary Program Source: |
01001112DB NSF RESEARCH & RELATED ACTIVIT 01001213DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
This Materials Interdisciplinary Research Team (MIRT) proposal examines the assembly and physical properties of new composite materials created by 'nano-laminating' atomic sheets of different van der Waals (vdW) materials. These vdW building blocks are materials in which the atomic bonds are strong in two directions, but weak in the third. This gives them a layered structure, like a stack of paper, and makes it easy to separate ('exfoliate') the layers. Common vdW materials include graphite, which can be exfoliated to form single sheets (graphene); many high-T superconductors; and layered chalcogenides such as MoS2. Many of these systems already display interesting behavior due to the low dimensionality of their electronic structure. The team pioneered a technique for re-stacking dissimilar vdW materials in a controlled fashion ('nano-lamination'). Using this technique, it is possible to create heterostructures that are essentially designer materials, with control at the level of the individual atomic layer. The aim of the MIRT is to create materials that provide unique functionality that is of interest to fundamental science and engineering applications.
The MIRT proposal includes a central synthesis effort that seeks to broaden the set of materials under study from the first examples (graphene and hexagonal boron nitride) to include layered chalcogenides, 2D oxides, topological insulators, and low-dimensional organic systems. The synthesis effort combines nano-lamination with single-crystal growth, molecular beam epitaxy, templated materials growth, and intercalation. Fundamental issues to be addressed include the nature of interfaces between dissimilar layers, how interlayer alignment changes properties, and 'design rules' for growth on vdW surfaces. The MIRT includes extensive characterization of the new materials by multiple techniques. These techniques include structural characterization, electronic transport, optical and Raman spectroscopy, scanned probe microscopy, and chemical methods.
Using the techniques and materials developed under the MIRT program, the team seeks to address a number of fundamental issues regarding behavior of materials in low dimensions. For instance, it will be possible to study the 3D-to-2D evolution of correlated electronic behavior such as superconductivity and charge density wave states as the host materials approach the limit of single atomic sheets. Likewise, nano-lamination will allow materials such as topological insulators and superconductors to be brought into proximity in order to probe exotic phases predicted to exist at these interfaces.
The MIRT team seeks to broaden the impact of its activities through REU and RET programs, as well as a school visitation program. In addition, a central goal of the MIRT is to strengthen interaction between Columbia and CCNY through better coordination of research and use of shared facilities, as well as joint student advising and recruiting.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
MIRT: “Building Functional Nanoarchitectures in van der Waals Materials”, Columbia University, City College of New York. NSF DMR-1122594
Project Outcomes
MIRT team has made a number of breakthroughs in the study of van der Waals materials and their heterostructures, including:
- Development of a technique to achieve multi-terminal contact to transition metal dichalcogenides (TMDs) encapsulated by crystalline hexagonal Boron Nitride (hBN). In this configuration, external scattering is decreased by two orders of magnitude. Low-temperature mobilities of over 10,000 cm2/Vs are achieved, and the first quantum oscillations in high magnetic field are observed.
- Detailed studies of the optical response of TMDs have yielded fundamental understanding of the optical excitations and bandstructure of these materials, including:
- broad-band measurements of the optical dielectric constants
- measurements of the Rydberg series and binding energy of excitons
- observation of charged excitons (trions) and biexcitons.
This work provides a foundation for detailed study and applications of TMDs in optoelectronics.
- Experimental demonstration of piezoelectricity in monolayer TMDs. This opens up the use of atomically thin materials for new types of strain sensing and actuation.
- Two observations of superconductivity at the surfaces of topological insulators. The first is in ‘Dirac Puddles’ at the surface of Sb2Te3, up to 60K. The second is at the interfaces of a multilayer structure Bi2Se3 / ZnxCd1-xSe / ZnxCdyMg1-x-ySe.
- Experimental and theoretical studies of the charge density wave state in NbSe2 that conclusively rule out one of two leading explanations for the origin of the CDW state.
The MIRT team built new research infrastructure in the form of an inert-atmosphere system for assembly of heterostructures; and implementation of an ‘auto-finder’ system for rapid identification of materials.
The MIRT sponsored successful REU and RET programs, and provided a test-bed for a comprehensive model for outreach to partner secondary schools. The Young Scholars program, begun in the summer of 2014, has grown into the Columbia Engineering School’s ENG program, its flagship local science/engineering outreach program.
Selected Publications
1. Lukas Zhao, Haiming Deng, Inna Korzhovska, Milan Begliarbekov, Zhiyi Chen, Erick Andrade, Ethan Rosenthal, Abhay Pasupathy, Vadim Oganesyan, and Lia Krusin-Elbaum, "Emergent surface superconductivity in the topological insulator Sb2Te3", Nature Communications vol. 6, Article number 8279 (2015).
2 Cui, X., Lee, G. H., Kim, Y. D., Arefe, G., Huang, P. Y., Lee, C. H., Chenet, D. A., Zhang, X., Wang, L., Ye, F., Pizzocchero, F., Jessen, B. S., Watanabe, K., Taniguchi, T., Muller, D. A., Low, T., Kim, P. & Hone, J. Multi-terminal transport measurements of MoS2 using a van der Waals heterostructure device platform. Nature Nanotechnology 10, 534-540, (2015).
3 Arguello, C. J., Rosenthal, E. P., Andrade, E. F., Jin, W., Yeh, P. C., Zaki, N., Jia, S., Cava, R. J., Fernandes, R. M., Millis, A. J., Valla, T., Osgood, R. M. & Pasupathy, A. N. Quasiparticle Interference, Quasiparticle Interactions, and the...
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