CAREER: Warm Quantum Materials: Harnessing Exotic Quantum Properties at High Temperatures

Non-technical Abstract:

Superconductivity is one of the most profound phenomena in condensed matter physics and has the property of complete absence of electrical resistance. Achieving a state of superconductivity at room temperature or near room temperature at ambient pressure is groundbreaking. Pressure has been proven to be the most versatile tuning parameter in making novel materials, such as superconductors.

Hydrogen-rich materials, mimicking the elusive solid metallic phase of hydrogen, can be metalized at much lower pressures, promoting high-Tc superconductivity at much lower pressures. The primary goal of this project is to synthesize novel hydrogen rich, room temperature or above room temperature superconducting materials at ambient pressure for practical applications, such as advanced power grids, new transportation, medical imaging, and scanning techniques such as MRI and magnetocardiography, and faster, more efficient electronics for digital logic and memory device technology.

The project also provides an important research infrastructure for high pressure experiments with capabilities of addressing a diverse set of problems in materials science. The principal investigator will create educational media to support teaching and student learning all over the world. Groups receiving direct support include graduate students gaining access to large user facilities and learning necessary research skills; local high school teachers collaborating with the principal investigator on direct application of classroom concepts; research opportunities for first-generation college, low-income, and underrepresented minority students; and improving and building upon resources available to the Deaf community.

Technical Abstract:

The properties of quantum materials are anomalously sensitive to external stimuli such as pressure, which give rise to exotic and often unprecedented properties. The long-standing quest for room-temperature or warm superconductivity has been reinvigorated by the discovery of high Tc superconductivity in a new class of dense, hydrogen-rich materials—superhydrides.

The superhydrides rely on the role of the dissociation of the hydrogen molecules, which provide the extra electrons needed in energy states near the Fermi level. However, thus far, theoretical and experimental studies are mainly focused on binary superhydrides. The efforts envisioned in this project represent a natural and timely research direction to discover and understand structure, chemical bonding, and stability of novel ternary and quaternary superconductors with Tc comparable to or higher than room temperature and via compositional tuning, lowering the transition pressure while preserving the superconducting properties.

Furthermore, in order to understand the quantum nature of these hot superconductors, there is a major need for absolute temperature measurements in high pressure experiments. To remedy this need, Nitrogen vacancy centers provide a new way to potentially determine the in-situ temperature measurement for compressed materials into the Mbar range, which would be revolutionary.

Careful thermal measurements would likely increase the ability to measure the heat capacity on superconducting superhydrides, which is a superior test for superconductivity. The work will allow the research team to obtain insight into superconductivity more broadly including the stabilities, and as such, to the design of a new class of warm quantum materials for transformative technologies.

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.