| NSF Org: |
DMR Division Of Materials Research |
| Recipient: |
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| Initial Amendment Date: | July 23, 2018 |
| Latest Amendment Date: | July 23, 2018 |
| Award Number: | 1809649 |
| 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: | August 1, 2018 |
| End Date: | July 31, 2022 (Estimated) |
| Total Intended Award Amount: | $484,937.00 |
| Total Awarded Amount to Date: | $484,937.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
910 GENESEE ST ROCHESTER NY US 14611-3847 (585)275-4031 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
518 Hylan Building Rochester NY US 14627-0140 |
| 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
Non-technical Abstract: Superconductors, which conduct electricity without resistance, are among the most fascinating materials in condensed matter physics. Achieving a state of superconductivity at room temperature or near room temperature will revolutionize our energy production and transportation system and will enhance economic growth and quality of life. Pressure has been proven to be the most versatile tuning parameter in making novel materials with exotic properties such as superconductivity. Solid metallic hydrogen, the high pressure phase of hydrogen, is predicted to have room temperature superconductivity. However, it requires extreme pressure. Hydrogen-rich materials, mimicking the elusive solid metallic phase of hydrogen, may lead to high-Tc superconductivity at much lower pressures. The primary goal of this project is to synthesize novel hydrogen-rich superconducting materials at high pressure temperature conditions and explore their possible room temperature superconductivity. Progress on this project can provide greater clarity regarding superconducting mechanisms. In turn, it may allow us to obtain insight into designing new superconducting materials in large quantities at ambient pressure. Through a comprehensive outreach approach, the principal investigator will recruit and mentor high school students to provide experiences to foster their scientific inquiry and communication skills. A goal of the outreach is to reach students who are underrepresented in the areas of science, technology, engineering, and mathematics. The principal investigator works with the University of Rochester's McNair program, whose mission is to increase the numbers of low-income, first generation, and underrepresented minority undergraduates who pursue PhD degrees.
Technical Abstract: Superconductivity has been one of the most arcane quantum phases in condensed matter physics. Solid metallic hydrogen is theorized to have the high Debye temperature and strong electron-phonon coupling that are necessary for high-Tc phonon-mediated superconductivity. However, it requires extreme pressure. As an alternative, hydrogen-rich materials, mimicking the elusive solid metallic phase of hydrogen, can be metalized at much lower pressures, providing large hydrogen-derived electronic density of states at the Fermi level and large modifications of the electronic structure in response to the motion of hydrogen atoms (electron-phonon coupling). The primary goal of this research is to synthesize novel hydrogen rich superconducting materials that are either known or likely to exhibit high Tc superconductivity. State-of-the-art high pressure and high temperature techniques, laser spectroscopy, and low temperature techniques in conjunction with novel transport measurements are used to synthesize and probe high temperature superconductivity. Success on this project elucidates greater clarity in superconducting mechanisms. In turn, it may allow the research team to obtain insight into designing new superconducting materials in large quantities at ambient pressure. The project also provides graduate students hands-on experience with cutting-edge nano-fabrication technologies and large user facilities, such as synchrotron and neutron facilities. In addition, the project offers summer internships to local high school students, and the principal investigator works with the University of Rochester's McNair program, whose mission is to increase the numbers of low-income, first generation, and underrepresented minority undergraduates who pursue PhD degrees, to recruit and mentor students.
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 primary goal of this project is to explore novel hydrogen-rich materials, as a potential high temperature superconductor, possibly comparable to or higher than room temperature by tuning the energy density of matter. Our approach is to investigate both covalent type hydrides contain low z materials such as C and S and as well as rare earth metal hydrides such as Y, La, and Ce for potential high temperature superconducting materials. In doing so, we integrated a photochemical induced new synthesis technique that was never used for high pressure experiments and developed new methods to measure superconducting properties using heat capacity and magnetic susceptibility at extreme conditions.
The major outcomes of this projects are summarized as the following:
(i) Discovery of room temperature superconducting in a photochemically transformed carbonaceous sulfur hydride, which superconducts at 288 K at 270 GPa, the highest Tc ever confirmed in a superconducting material. In addition, we have shown that via compositional tuning of the carbon content, the pressure required to be superconducting can to 130 GPa. This discovery has shown to be a way forward to lower the required pressures for superconductivity while still maintaining very high critical transition temperatures compared to the H2S and H2S+H2 derived superconductors.
(ii) Discovery of yttrium superhydride, which superconducts at 262 K at around 180 GPa. In this study, we present a novel synthesis approach to synthesize rare earth metal hydride. A thin film of palladium, which is known to promote catalytic hydrogenation across a range of systems, is used to prevent oxidation of sputtered yttrium and promote a room temperature transformation of yttrium metal and H2 into yttrium hydride.
(iii) Development of modulation AC susceptibility method to detect a superconducting transition in smaller samples. This is a highly sensitive method, with nearly constant background with temperature compared to the standard method. In our design, we use a 4-coil system in which the modulation field is applied through the superposition of excitation and modulation signals in the primary coils. This approach eliminates the need for a separate modulation coil and allows the positioning of the sample to be in the center of the modulation (i.e. primary) coil, maximizing the flux density at the sample space. In addition, a dual mode capability of modern lock-in amplifiers eliminates the need for additional lock-in amplifier use, which significantly simplifies the complexity and reduces the cost, while maintaining a high sensitivity to observe superconducting transitions from small samples.
(iv) Development of a heat capacity measurement method to detect superconducting transition at high pressure conditions. Typically, at ambient conditions, specific heat is measured using an adiabatic technique. This method works well when the samples are relatively large, and the sample mount is reasonably small. The requirements to achieve adiabatic conditions fail when higher pressures are desired. We used a Joule heater, and a thermocouple is connected directly to the sample and by measuring the second harmonic voltage response on the thermocouple with respect to the heater drive, a semi-quantitative specific heat value was obtained. This method is demonstrated by carrying out measurements around the superconducting transition of MgB2 at 1.5 GPa.
(v) Development of a new method to directly measured electrical resistance of graphene at high pressures.
The scientific understanding obtained during this project on design, synthesis, and structural and physical characterization of novel hydrides with high superconducting transition temperatures, and the understanding of how to access metastable pathways to their recovery to ambient conditions, is setting the stage for potential revolutionary progress in room temperature superconducting materials, which can be used for transformative technologies by design.
As a result of this project, we produced fourteen (14) peer-reviewed manuscripts and 10 of them are published, while 4 are under review, including an invited review article. Two of the peer-reviewed articles were featured articles with editors? suggestion and reported in many popular presses including New York Times and The Wall Street Journals. Additionally, two patents have been filed for the discovery of high Tc temperature superconductors. This project produced two Ph.D.'s at University of Rochester in the disciplines of Physics and Astronomy and Mechanical Engineering as well as supported 11 undergraduate research projects.
Last Modified: 04/22/2023
Modified by: Ranga Dias
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