Twisted Graphene Sheets Reveal 'Unconventional' Superconductivity Governed by Quantum Geometry (sciencealert.com) 6
Twisting two atomically thin sheets of graphene enables "a host of exceptional properties," writes MIT News, "including unconventional superconductivity." (Which makes this graphene "a promising building block for future quantum-computing devices.")
And now "We find the superfluid stiffness to be much larger than expected..." a team of researchers reported this week in Nature. Hackaday explains that "Part of the problem has been that it is hard to make large pieces of multi-layer graphene. By creating two-ply pieces and using special techniques, an international team is finding that quantum geometry explains how graphene superconductors resist changes in current flow more readily than conventional superconductors."
Or, as Science Alert puts it, "Forced to run a labyrinth of carbon atoms uniquely arranged in twisted stacks, electrons do some rather peculiar things." Researchers from the University of British Columbia in Canada, the University of Washington and Johns Hopkins University in the US, and the National Institute for Materials Science in Japan recently discovered a strange new state of matter in the dynamics of currents flowing through layers of graphene.
The findings confirm predictions on how electrons ought to behave when squeezed into crystalline arrangements, and may contribute fresh ideas on how to achieve reliable approaches to quantum computing or reveal ways to develop room-temperature superconduction... Graphene has been increasingly seen as something of a wonder material over recent decades, its lattice of carbon atoms connected in a way that leaves spare electrons to leap about like tokens in a game of quantum checkers. Physicists have consistently bent the rules of this game, finding new and unusual ways to alter properties of resistance or coordinate into exotic states. For these reasons, graphene has become a perfect playground to search for clues on low-resistance conductivity or test the boundaries of various quantum effects.
This week MIT research scientist Joel Wang (a co-lead on the study) said "There's a whole family of 2D superconductors that is waiting to be probed, and we are really just scratching the surface." New Scientist explores where their research could lead: Why do cold thin sheets of carbon offer no resistance to electric currents? Two experiments are bringing us closer to an answer — and maybe even to practical room-temperature superconductors... Past experiments have shown that very cold stacks of two or three layers of graphene can superconduct, or perfectly conduct electricity without resistance and energy loss, if some of the sheets are rotated by a special angle. But why this happens remained mysterious... [B]oth teams had to innovate a setup where the tiny graphene flakes were exposed to microwaves while the researchers slowly varied properties like temperature, which must be kept very low for superconductivity to occur at all...
"We are finding interesting laws which seem to emerge in both these material systems. Maybe what we are uncovering is something deeper," says [Harvard postdoctoral researcher Abhishek Banerjee]. Both teams are planning on performing similar experiments with other very thin superconductors.
And now "We find the superfluid stiffness to be much larger than expected..." a team of researchers reported this week in Nature. Hackaday explains that "Part of the problem has been that it is hard to make large pieces of multi-layer graphene. By creating two-ply pieces and using special techniques, an international team is finding that quantum geometry explains how graphene superconductors resist changes in current flow more readily than conventional superconductors."
Or, as Science Alert puts it, "Forced to run a labyrinth of carbon atoms uniquely arranged in twisted stacks, electrons do some rather peculiar things." Researchers from the University of British Columbia in Canada, the University of Washington and Johns Hopkins University in the US, and the National Institute for Materials Science in Japan recently discovered a strange new state of matter in the dynamics of currents flowing through layers of graphene.
The findings confirm predictions on how electrons ought to behave when squeezed into crystalline arrangements, and may contribute fresh ideas on how to achieve reliable approaches to quantum computing or reveal ways to develop room-temperature superconduction... Graphene has been increasingly seen as something of a wonder material over recent decades, its lattice of carbon atoms connected in a way that leaves spare electrons to leap about like tokens in a game of quantum checkers. Physicists have consistently bent the rules of this game, finding new and unusual ways to alter properties of resistance or coordinate into exotic states. For these reasons, graphene has become a perfect playground to search for clues on low-resistance conductivity or test the boundaries of various quantum effects.
This week MIT research scientist Joel Wang (a co-lead on the study) said "There's a whole family of 2D superconductors that is waiting to be probed, and we are really just scratching the surface." New Scientist explores where their research could lead: Why do cold thin sheets of carbon offer no resistance to electric currents? Two experiments are bringing us closer to an answer — and maybe even to practical room-temperature superconductors... Past experiments have shown that very cold stacks of two or three layers of graphene can superconduct, or perfectly conduct electricity without resistance and energy loss, if some of the sheets are rotated by a special angle. But why this happens remained mysterious... [B]oth teams had to innovate a setup where the tiny graphene flakes were exposed to microwaves while the researchers slowly varied properties like temperature, which must be kept very low for superconductivity to occur at all...
"We are finding interesting laws which seem to emerge in both these material systems. Maybe what we are uncovering is something deeper," says [Harvard postdoctoral researcher Abhishek Banerjee]. Both teams are planning on performing similar experiments with other very thin superconductors.
Promises (Score:1)
Re: (Score:2)
So, next year.
Pleasant surprise (Score:2)
We find the superfluid stiffness to be much larger than expected...
Man... If I had a nickle every time I've heard that. :-)
(Ya, in know ...)
TL;DR (Score:2)
Re: (Score:2)
Do you want me to ChatGPT that for you?
Heh. (Score:1)
Got to be pretty unconventional to count as unconventional in QM.