| NSF Org: |
DMR Division Of Materials Research |
| Recipient: |
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| Initial Amendment Date: | April 2, 2021 |
| Latest Amendment Date: | May 21, 2021 |
| Award Number: | 2105139 |
| Award Instrument: | Standard 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: | July 1, 2021 |
| End Date: | June 30, 2024 (Estimated) |
| Total Intended Award Amount: | $240,000.00 |
| Total Awarded Amount to Date: | $240,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
800 WEST CAMPBELL RD. RICHARDSON TX US 75080-3021 (972)883-2313 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
800 West Campbell Road Richardson TX US 75080-3021 |
| 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: |
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| 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
Nontechnical Abstract:
This collaborative project studies special materials known as two-dimensional materials such as metal chalcogenides. Recent predictions indicate that these materials have interesting properties. The project aims to develop these properties using externally applied electric and magnetic fields in order to gain knowledge that will promote development of quantum information processing and quantum computing technologies. The project is integrated with educational activities to train graduate students and involve undergraduate and pre-college students in research. The project also enables the PIs to continue their successful mentoring of members from underrepresented groups.
Technical Abstract:
A basic building block of quantum circuits is the quantum bit or qubit. Recent recognition that higher-dimensional quantum states known as qudits have many potential advantages towards quantum information processing has generated much focus on this topic. These pertain to areas such as quantum simulation, quantum communications, fundamental tests of quantum mechanics, and improved quantum error correction. This project uses two-dimensional metal chalcogenides? unique band structures comprising multiple valleys to realize high-dimensional quantum qudit states based on multiple flavor degrees of freedom. These materials have a predicted flavor SU(3) symmetry, of particular interest because of the analogy to the quark model in particle physics, and this symmetry is extremely rare in condensed matter systems. The project experimentally tests predictions for novel tunable Kondo effects and Coulomb blockade behavior emerging from this symmetry. The project also performs experiments aimed at manipulating these flavor states to develop qudits towards quantum information processing based on flavortronics. These research activities are coupled with a parallel theoretical effort that informs the experimental one, leading to a synergistic effort aimed at the development of high-dimensional quantum states based on beyond-graphene two-dimensional materials.
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.
A basic building block of quantum circuits is the quantum bit or qubit. Recent recognition that higher-dimensional quantum states known as qudits have many potential advantages towards quantum information processing has generated much focus on this topic. While quantum dots have been used as a basis for qubits, quantum dot implementations of qudits are limited. This collaborative project aimed to study 2D materials-based quantum dots to realize and investigate high-dimensional quantum states – qudits. Our team achieved significant progress through iterative feedback loops linking theory, computation, device fabrication, characterization, and external collaboration efforts.
Teamwork
We have theoretically and experimentally demonstrated that two outstanding families of 2D materials can host the targeted 3-fold valley symmetry for building qudits in quantum dot geometry. One is the transition metal dichalcogenides such as WSe2 and the other is ABC-stacked graphene systems such as AB bilayer and ABC trilayer. While the former are semiconductors, the latter are air-stable, of high-mobility, and easily contacted. For WSe2, we have obtained quantum dot and point contact devices, performed transport spectroscopy, and observed Coulomb blockade, Kondo-like resonance, magnetic field response, and excited states. For AB bilayer graphene quantum dots, we have performed compressibility measurements and identified magnetic phases and their boundaries.
External collaboration
One promising family of materials to realize qudits is ABC-stacked graphene systems. However, the ABC stacking is only metastable compared to the ABA stacking. To eliminate ABA-ABC domain walls that are known to easily move, converting the structure entirely to ABA stacking, Bockrath collaborated with the Ju group at MIT to perform near-field infrared measurements that are capable of distinguishing ABA- and ABC-stacked graphene domains. Zhang collaborated with the Weitz group in Germany and revealed the impact of 3-fold symmetry on interacting electrons’ phase diagram for AB bilayer graphene. Additionally, Zhang collaborated with the Lau group at OSU and identified the quantum octet states in pentagonal 2D PdSe2 and the quantum Hall quartet states in 2D InSe.
Other significant works
Our team made several other significant contributions to the field of quantum states in 2D materials. Bockrath and Zhang critically reviewed fabrication challenges and emergent physics of moiré materials and demonstrated a quantum geometric mechanism for understanding and designing flat-band superconductors. Zhang co-invented deep optical sensing and participated the discovery of a giant quantum anomalous Hall effect predicted by him in 2011.
Broader impacts
Our team collectively provided comprehensive training for 2 K12 students (1 female), 3 undergraduate students, 5 graduate students, and 2 postdocs. Among these trainees, 1 obtained Ph.D. degree, and 1 entered the Stanford graduate school STEM program. Notably, 2 students were honored with the Steven Weinberg Research Awards from the Texas Section of American Physical Society (APS), and 1 student received an internship from Sandia National Laboratory. Bockrath supervised Devin Ryan in a senior thesis project aimed at increasing the yield of single layer flakes from exfoliation. As a result, Devin graduated with a research distinction. Bockrath also supervised Xuanzhi Zhang, who worked on developing machine learning algorithms to identify 2D material monolayers towards an automated search and identification system. He is now in the USC graduate program in computer science.
For the total solar eclipse on April 8, 2024, Zhang delivered 200 pairs of solar viewing glasses to Canyon Creek Day School in Plano, TX for free and introduced ARI THE ASTRONOMER’S SOLAR ECLIPSE SAFETY COMIC BOOK to them. Zhang gave a keynote talk in a 2D materials workshop at San Sebastian, Spain, and the workshop was a registered summer course of the University of the Basque Country. Zhang organized 2 invited symposia relevant to this program in the APS March Meetings.
Last Modified: 11/12/2024
Modified by: Fan Zhang
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