Study reveals new class of moiré systems: opens opportunities for new quantum technologies

Scientists at the University of Minnesota Twin Cities in collaboration with researchers in Spain have demonstrated that twisting an anisotropic homobilayer can result in the collapse of the moiré pattern thereby changing the two-dimensional structure into a one-dimensional crystal. Their study indicates that twisted anisotropic homobilayers is a unique class of moiré systems that bears this distinct feature. The details of their research are presented in a paper titled, “Moiré collapse and Luttinger liquids in twisted anisotropic homobilayers,” published in the PNAS. 

The results throw open a new landscape in moiré physics that bears the potential for applications in quantum phenomena, nanoelectronics, and optoelectronics.  

Duarte J.P. de Sousa, one of the study authors, comments on the impact of their findings: "Our work reveals a new structural effect in two-dimensional crystal lattices, which we call 'moiré collapse.' By twisting two atomically thin anisotropic materials, it is possible to "collapse" the lattice structure into one-dimensional moiré crystals. This isn't just a geometric curiosity; it provides a robust new pathway to design quantum materials where electrons behave in highly unconventional ways potentially unlocking new capabilities for quantum technologies, optoelectronics and spintronics."

Moiré systems have played an important role in inducing electronic states in two-dimensional material systems. They lend themselves to precise control of their lattice arrangement which facilitates fine tuning of their electronic structures. Increased tunability in turn makes for the potential to emulate other materials. Most studies of moiré systems have focused on isotropic two-dimensional materials leaving those derived from twisted anisotropic homobilayers less explored. In the current study, researchers present an as yet unexplored feature of moiré systems, the collapse of the two-dimensional moiré pattern into a one-dimensional lattice structure in anisotropic two-dimensional materials. The observed phenomenon is called the moiré collapse and is present universally in twisted anisotropic homobilayers. The team have found that the anisotropy in such a material can be increased by changing the twist angle, with the moiré pattern ultimately collapsing when the angle approaches a “collapse magic angle” near 90 degrees. After the collapse, the team noticed that the material displayed one-dimensional electronic behavior, with conditions becoming ideal for the emergence of a Luttinger liquid state. 

Scientists expect that the change in the behavior could have a significant impact on nonlinear electron transport and optical behavior with the potential for opening new frontiers in the engineering of novel electronic phases.

Funding statement: The research was funded by the Office of Naval Research, the National Science Foundation, the Spanish Ministry of Science, Innovation and Universities (MICIU), along with the State Research Agency of Spain (AEI) and the European Regional Development Fund (FEDER/UE), and Comunidad de Madrid.

The research team comprised members from the Department of Electrical and Computer Engineering (Paul Palmberg Professor Tony Low, Seungjun Lee and Duarte J. P. de Sousa) and Francisco Guinea of Instituto Madrileño de Estudios Avanzados Nanoscience in Madrid, Spain and Donostia International Physics Center in San Sebastián, Spain.

Read the complete paper at the PNAS website. 

Co-author Duarte J.P. de Sousa received his doctoral degree under the supervision of Professor Tony Low in 2023, subsequently serving as a postdoctoral researcher until the summer of 2025. He is currently a research associate within the Physical Measurement Laboratory at the National Institute of Standards and Technology (NIST) in Gaithersburg, MD.