Physicists observe key evidence of unconventional superconductivity in magic-angle graphene

Good news! Sounds almost like Voodoo ("unconventional", "magic-angle")! 😊

Are we finally coming closer to room temperature superconductivity?

"... “magic-angle” twisted tri-layer graphene (MATTG) ...

 In particular, the team was able to measure MATTG’s superconducting gap — a property that describes how resilient a material’s superconducting state is at given temperatures. They found that MATTG’s superconducting gap looks very different from that of the typical superconductor, meaning that the mechanism by which the material becomes superconductive must also be different, and unconventional. ...

The researchers made their discovery using a new experimental platform that allows them to essentially “watch” the superconducting gap, as the superconductivity emerges in two-dimensional materials, in real-time. They plan to apply the platform to further probe MATTG, and to map the superconducting gap in other 2D materials — an effort that could reveal promising candidates for future technologies. ..."

From the abstract:

"Understanding the nature of superconductivity in magic-angle graphene remains challenging. A key difficulty lies in discerning the different energy scales in this strongly interacting system, particularly the superconducting gap.

Here, we report simultaneous tunneling spectroscopy and transport measurements of magic-angle twisted trilayer graphene.

This approach allows us to identify two coexisting V-shaped tunneling gaps with different energy scales:

a distinct low-energy superconducting gap that vanishes at the superconducting critical temperature and magnetic field, and

a higher-energy pseudogap.

The superconducting tunneling spectra display a linear gap-filling behavior with temperature and magnetic field and exhibit the Volovik effect, consistent with a nodal order parameter.

Our work suggests an unconventional nature of the superconducting gap and establishes an experimental framework for multidimensional investigation of tunable quantum materials."

MIT physicists observe key evidence of unconventional superconductivity in magic-angle graphene | MIT News | Massachusetts Institute of Technology "The findings could open a route to new forms of higher-temperature superconductors."

Experimental evidence for nodal superconducting gap in moiré graphene (no public access)

Experimental evidence for nodal superconducting gap in moiré graphene (manuscript, open access)