CAREER: Investigating unconventional superconductivity with reconfigurable graphene heterostructures

Nontechnical Description Since their discovery a century ago, understanding superconductors, which are electronic materials that exhibit zero resistance to electrical current, as well as seeking superconductors with higher working temperatures, have been central objectives in modern physics research, both for their tremendous applicational potential and for fundamental understanding of nature. This CAREER project focuses on developing new tools for investigating a novel class of graphene-based superconductors, understanding the root of their superconductivity, and investigating how to make them work at higher temperatures. This research project also brings significant educational and societal impacts, including outreach activities for undergraduate students, high school students, and to-be K-12 teachers. These activities strengthen the connections among UC Berkeley, other minority-serving institutes, and underrepresented K-12 schools in the California Bay area. The PI also develops a new quantum materials course that supplements the UC Berkeley curriculum with frontier developments in research and will deliver many next-generation quantum-equipped engineers to the US STEM workforce during the span of this CAREER project. Technical Description Recently, graphene-based van der Waals (vdW) heterostructures have emerged as clean, highly tunable, and rich platforms for investigating unconventional superconductivity and other exotic quantum phenomena. However, there are several fundamental challenges in these materials that urgently need resolution to advance the knowledge in this field. The primary research goal of this project is to develop a toolbox to study graphene heterostructures in a reconfigurable manner and use it to elucidate important questions about unconventional superconductivity in these heterostructures, establishing a platform to investigate new quantum phenomena and build new quantum devices. To achieve these specific goals, the PI builds upon his extensive expertise on 2D moiré heterostructures, superconductivity, and on-chip electromechanical devices. The outcomes from this project will answer the following important questions: 1) What are the necessary conditions to induce unconventional superconductivity in twisted and untwisted graphene heterostructures? 2) What is the mechanism behind the enhancement of this unconventional superconductivity by proximity to monolayer transitional metal dichalcogenides? These answers are of utmost importance for designing next-generation superconductors with higher transition temperatures. This knowledge can lead to the development of smaller, more efficient electronic devices and quantum computers, enhance power grid efficiency, and improve technologies relying on strong magnetic fields like MRI and maglev trains. This research also provides deeper insights into quantum mechanics and condensed matter physics, potentially uncovering new physical phenomena and exotic states of matter. 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.