IRG1 2D Polar Metals and Heterostructures pursues the promise of a new materials platform that stabilizes a diverse array of two-dimensional polar metals and enables their integration into ground-breaking optically and electronically active heterostructures. 


Co-Leaders: Jun Zhu, Josh Robinson, and Ken Knappenberger


Metals and alloys sit at the heart of materials research, but their susceptibility to surface oxidation has impeded their investigation in atomically thin form or as pristine surfaces exposed to the ambient environment. Thus, metals are generally not considered to be electrostatically gateable, rarely strongly polar, and typically not straightforward constituents of complex quantum hetero-structures due to interfacial reactions.   IRG1 surmounts these challenges and opens up new areas of fundamental science and application for metals and their alloys through in-situ encapsulation and heterostructure formation that takes advantage of the protected high-energy interface underneath epitaxial graphene and exploits a self-healing effect that yields air-stable atomically thin crystalline metals that are also polar, with exceptional nonlinear optical response and intriguing potential for impacts in quantum devices and biosensing. 

The IRG converges expertise in synthesis, optics and spectroscopy, transport, spintronics, device engineering, biosensing, theory and data-driven computation to exploit the unique opportunities in fundamental science and application afforded by air-stable crystalline 2D metals and alloys. These efforts will be accelerated by predictive computation to guide synthesis and application within the expansive compositional design space that CHet endows, and will open new routes to Quantum Leap, enable new sensing modalities for elucidating the Rules of Life, and provide an intriguing venue to Harness the Data Revolution. The team's efforts are organized around quantum and optical property domains, tied together by a central thrust in synthesis of novel structures, compositions and heterostructures of air-stable polar 2D metals.


Recent Publications

Interface-induced superconductivity in magnetic topological insulators. Science. 383, 6683, 2024DOI:10.1126/science.adk1270

Electrical switching of the edge current chirality in quantum anomalous Hall insulators. Nature Materials. 23, 58-64, 2024. DOI: 10.1038/s41563-023-01694-y

Electrically Controlled Anomalous Hall Effect and Orbital Magnetization in Topological Magnet MnBi2Te4. Physical Review Letters. 132, 066604, 2024DOI: 10.1103/PhysRevLett.132.066604 

3D Quantum Anomalous Hall Effect in Magnetic Topological Insulator Trilayers of Hundred-Nanometer Thickness. Advanced Materials. 2023. DOI: 10.1002/adma.202310249

Dirac-fermion-assisted interfacial superconductivity in epitaxial topological-insulator/iron-chalcogenide heterostructures. Nature Communications. 14, 7119, 2023. DOI: 10.1038/s41467-023-42902-2

Strain-Induced 2H to 1T′ Phase Transition in Suspended MoTe2 Using Electric Double Layer Gating. ACS Nano. 17, 22, 22388-22398, 2023. DOI: 10.1021/acsnano.3c04701


Publications that report work supported by the MRSEC should include an acknowledgement in the form "ABC and XYZ acknowledge support from the Penn State Materials Research Science and Engineering Center Center for Nanoscale Science under National Science Foundation award DMR-2011839." If all co-authors performed their work under MRSEC support, then the ABC/XYZ initials can be omitted. Work produced using MRSEC facilities should include an acknowledgement thereof as described on the facilities pages.