Experiment maps superconductivity and switchable orbital magnetism in rhombohedral graphene

An experiment on semimetallic rhombohedral hexalayer graphene has revealed a phase diagram containing correlated insulators, several pockets of superconductivity and two distinct multiferroic orbital magnetic orders. The study focuses on the semimetallic regime, in which the material’s conduction and valence bands overlap, rather than the previously studied regime in which those bands remain separated. The results, reported in Nature Physics , show that this band-overlap regime supports a variety of correlated and potentially topological quantum phases within a single layered carbon system.

Two superconducting-like states were observed near a band inversion. Both were confined to regions where electron and hole Fermi surfaces coexist, a restriction that is consistent with a possible dual-carrier origin for superconductivity. The observation suggests that the presence of both carrier types may be relevant to the superconducting phases, but the reported results do not establish the microscopic pairing mechanism.

The experiments also identified a ferroelectric orbital magnetic state with a sharply switchable magnetic response. Its magnetism reverses under a unipolar electric field, and the magnetic hysteresis is itself reversible by the electric field. This behavior is consistent with a phenomenological model of coupled electric and magnetic polarization.

Unlike previously reported multiferroicity near zero electric field, the newly identified state switches under a unipolar field, which the authors interpret as a signal of spontaneous electric polarization. The observations therefore link an orbital magnetic order with an electrically switchable ferroelectric response, rather than merely showing that magnetic and electric properties occur in the same sample. Overall, the study expands the experimental phase map of rhombohedral graphene into an overlapping-band semimetallic regime.

It demonstrates that this regime can accommodate correlated insulating behavior, multiple superconducting-like pockets and two separate multiferroic orbital magnetic orders. The possible connection between electron and hole Fermi surfaces and superconductivity remains a mechanistic question, while the evidence for spontaneous electric polarization comes from field-reversible magnetic switching and its consistency with the coupled-polarization model. Together, the results identify rhombohedral hexalayer graphene as a platform in which superconductivity, orbital magnetism and ferroelectric behavior can be investigated within the same correlated semimetal, although the preview does not provide the full experimental details needed to assess those phases in greater depth.

Subject of Research: Experimental mapping of superconductivity and ferroelectric orbital magnetism in semimetallic rhombohedral hexalayer graphene

Article Title: Superconductivity and ferroelectric orbital magnetism in semimetallic rhombohedral hexalayer graphene

Article References: Deng, J., Xie, J., Li, H., Taniguchi, T., Watanabe, K., Shan, J., Mak, K. F., & Liu, X. (2026). Superconductivity and ferroelectric orbital magnetism in semimetallic rhombohedral hexalayer graphene. Nature Physics. https://doi.org/10.1038/s41567-026-03443-9

Image Credits: AI Generated

DOI: 10.1038/s41567-026-03443-9

Keywords: rhombohedral graphene, hexalayer graphene, semimetal, superconductivity, orbital magnetism, ferroelectricity, multiferroicity, band inversion, quantum phases, correlated electrons, ferroelectric, orbital