Scientists have noticed a quantum fluid of electrons in graphene for the primary time, displaying near-perfect fluid behaviour and shedding mild on a quantum physics puzzle.
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In a collaborative effort, researchers on the Indian Institute of Science and Japan’s Nationwide Institute for Supplies Science have captured an elusive fluid state in graphene. The research was printed in Nature Physicsand makes an attempt to reply the query of whether or not electrons behave like an ideal, frictionless fluid.
Atomic imperfections and impurities in supplies has meant it’s exceptionally troublesome to discover this electron behaviour. Nevertheless, the brand new research, with ultra-clean graphene samples, could have discovered a method round this.
It’s wonderful that there’s a lot to do on only a single layer of graphene even after 20 years of discovery.
Arindam Ghosh, Research Corresponding Writer and Professor, Division of Physics, Indian Institute of Science
The researchers created exceptionally clear graphene samples and examined how they conduct each electrical energy and warmth. What they discovered was stunning: the 2 sorts of conductivity have been inversely proportional. When electrical conductivity rose, thermal conductivity dropped, and vice versa.
This relationship contradicts a widely known idea referred to as the Wiedemann-Franz rule, which states {that electrical} and thermal conductivity values ought to be exactly associated. On this case, the connection broke down by an element of greater than 200 at low temperatures.
The researchers discovered that each cost and warmth conduction within the graphene samples relied on a material-independent common fixed equal to the quantum of conductance, a primary worth linked to the motion of electrons.
The weird behaviour was most outstanding close to the “Dirac level,” a state the place graphene behaves as neither a steel nor an insulator. At this level, electrons cease performing like particular person particles and as an alternative circulation collectively as a collective, low-viscosity fluid. The fluid behaves equally to water, however a couple of hundred occasions much less viscous.
Since this water-like conduct is discovered close to the Dirac level, it’s referred to as a Dirac fluid – an unique state of matter which mimics the quark-gluon plasma, a soup of extremely energetic subatomic particles noticed in particle accelerators at CERN.
Aniket Majumdar, Research First Writer and PhD Scholar, Division of Physics, Indian Institute of Science
The scientists additionally evaluated the viscosity of this Dirac fluid and found that it was the closest factor to an ideal fluid, minimally viscous.
The findings might make graphene a possible low-cost platform for laboratory investigations into high-energy physics and astrophysics points reminiscent of black gap thermodynamics and entanglement entropy scaling.
From a technological standpoint, the presence of Dirac fluid in graphene has vital purposes in quantum sensors which might be able to amplifying very weak electrical alerts and monitoring extraordinarily weak magnetic fields.
Journal Reference:
Majumdar, A., et al. (2025) Universality in quantum important circulation of cost and warmth in ultraclean graphene. Nature Physics. doi.org/10.1038/s41567-025-02972-z
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