By developing a novel technique to get a \u201cdirect view\u201d of its properties, MIT physicists have reported a significant breakthrough, providing the most direct evidence to date of unconventional superconductivity in \u201cmagic-angle\u201d twisted tri-layer graphene (MATTG).\u00a0<\/p>\n
The discovery provides new confirmation that the material, composed of three stacked and twisted atom-thin carbon sheets, is a unique type of superconductor.<\/p>\n
This finding is a crucial step in the global search for room-temperature superconductors, often referred to as the \u201cHoly Grail\u201d of physics.\u00a0<\/p>\n
\u201cThis direct view can reveal how electrons pair and compete with other states, paving the way to design and control new superconductors and quantum materials that could one day power more efficient technologies or quantum computers,\u201d said co-lead author Jeong Min Park.\u00a0<\/p>\n
While conventional superconductors are extremely energy-efficient, they only work at ultra-low temperatures, limiting their practical use.\u00a0<\/p>\n
A superconductor that works at higher, more practical temperatures could revolutionize technology, enabling everything from zero-energy-loss power grids and practical quantum computers to more efficient MRI machines.<\/p>\n
Direct measurement of superconducting gap<\/p>\n
The research team\u2019s breakthrough lies in their direct measurement of MATTG\u2019s \u201csuperconducting gap\u201d\u2014a property describing the resilience of its superconducting state<\/a>.\u00a0<\/p>\n They discovered that this gap has a distinct V-shaped profile, which is fundamentally different from the flat, uniform gap found in conventional superconductors.\u00a0<\/p>\n This difference confirms that the mechanism causing superconductivity in MATTG must also be unconventional.<\/p>\n Novel experimental platform<\/p>\n To achieve this, the researchers developed a novel experimental platform.\u00a0<\/p>\n \u201cThe new technique combines electron tunneling with electrical transport \u2014 a technique that is used to gauge a material\u2019s superconductivity, by sending current through and continuously measuring its electrical resistance (zero resistance signals that a material is superconducting),\u201d added the team in a press release<\/a>.<\/p>\n This combination allowed the team to unambiguously link the V-shaped gap directly to the material\u2019s superconductivity.<\/p>\n \u201cThe superconducting gap gives us a clue to what kind of mechanism can lead to things like room-temperature superconductors that will eventually benefit human society,\u201d said Shuwen Sun, study co-lead author and a graduate student in MIT\u2019s Department of Physics.<\/p>\n Distinct pairing mechanism and future work<\/p>\n