| NSF Org: |
DMR Division Of Materials Research |
| Recipient: |
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| Initial Amendment Date: | May 12, 2020 |
| Latest Amendment Date: | August 18, 2021 |
| Award Number: | 2003343 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Tomasz Durakiewicz
tdurakie@nsf.gov (703)292-4892 DMR Division Of Materials Research MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | August 1, 2020 |
| End Date: | December 31, 2023 (Estimated) |
| Total Intended Award Amount: | $553,954.00 |
| Total Awarded Amount to Date: | $584,472.00 |
| Funds Obligated to Date: |
FY 2021 = $403,894.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
140 COMMONWEALTH AVE CHESTNUT HILL MA US 02467-3800 (617)552-8000 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
MA US 02467-3804 |
| 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): | CONDENSED MATTER PHYSICS |
| Primary Program Source: |
01002122DB NSF RESEARCH & RELATED ACTIVIT 01002223DB 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
Non-Technical Abstract:
In recent years a new kind of phase of matter has been predicted, called a Higher Order topological state. This state contains specific new modes on intersections of different surfaces of the crystal. These so-called "hinge" or "corner" modes have the potential to form the basis of future topological quantum computers, immune to errors and able to perform calculations currently unthinkable. An exciting example of such materials is FeTeSe, where the PI provided the first evidence that it is a higher order topological superconductor. Using expertise in fabrication, electrical, and optical spectroscopy, the PI will develop new means to probe the properties of the hinge modes in FeTeSe systematically. The topics and techniques also provide an excellent starting point for creating public talks and recruiting a diverse set of trainees, undergraduate and graduate students, who also participate in public outreach. The project's participants gain valuable professional skills in: collaboration, computation, fabrication, and characterization.
Technical Abstract:
Higher order topological phases have recently emerged, with boundary modes in two or more dimensions smaller than the bulk. These are systems whose boundary states are themselves topological, gapped with different signs. Using his expertise in fabrication, electrical, and optical spectroscopy, the PI will develop new means to probe the properties of the hinge modes in FeTeSe. An array of contact configurations and protocols will determine the best method to isolate the hinge from the bulk. This effort is aided by photothermal measurements to image the hinges. Careful studies of the effects of magnetic fields and magnetic contacts will determine the details of spin momentum locking. The studies will reveal the transport, thermal, and spin-momentum locking of the hinge modes. As such, their robustness will be directly probed, along with determining the proper ground-state Hamiltonian to describe the hinges.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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.
The project focused on exploring a new topological state of matter based on a unique superconductor, FeTeSe. This superconductor was predicted to host a new quasi-particle called a hinge mode. This mode exists at the intersection between two surfaces, making its detection very challenging. Nonetheless, the discovery of the mode would herald the onset of a new state of matter. In addition, the mode could form the basis of a future quantum computer completely free from error. To explore this mode, the PI has previously made electrical contacts to the hinge, the side, and the top of the material. The electrical conductance in the superconducting suggested the presence of a new mode.
With this in mind, the PI and his team endeavored to discover the best means to fabricate devices with these materials and develop the protocols to measure this hinge mode. This included optimizing the preparation of the material, and its characterization with Atomic Force, Transmission Electron, and Energy Dispersive X-ray microscopes. The information provided by this characterization allowed the PI to make electrical contacts to a single hinge. Using such contacts, the PI discovered a nonlocal signal that only emerges in the superconducting state, guaranteeing the non-trivial topological nature of the hinge mode. This work and the techniques developed resulted in five publications.
In addition, the project allowed the PI to train a postdoc, three graduate students from diverse backgrounds, seven undergraduates, and a high school student in cutting-edge nanofabrication techniques. These students also were exposed to new ideas at the forefront of modern quantum technologies. Lastly, the PI and his students participated in the Skype a Scientist program to connect with K-12 classrooms across the US and Canada.
Last Modified: 01/08/2024
Modified by: Kenneth S Burch
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