Electrons Race Down a Quantum Highway express

Original: "Demonstration of a Field-Effect Three-Terminal Electronic Device with an Electron Mobility Exceeding 40 Million cm^2/(Vs)"
arXiv:2601.15418 · 2026-01-21 · CC BY 4.0 · 1 min
Physicists double the record for electron mobility in a transistor by assembling the device without damaging the ultraclean material.

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Imagine a superhighway where cars zoom along with barely a slowdown: that's what a layer of ultraclean semiconductor looks like, where electrons travel vast distances without a single collision. Scientists have built a transistor in which electrons run twice as fast as in any similar device before.

Usually, when you turn such a material into an electronic device, you inevitably scratch it, contaminate it, and heat it, and the road gets ruined. Here, they did things differently: all the steps for creating contacts and gates were done on a separate sapphire wafer, which was then flipped over and gently pressed onto the clean material. It's like building a bridge on the shore and then lowering it onto the road without touching the asphalt.

Record electron mobility: 40 million square centimeters per volt-second. That's like a sprinter running the 100-meter dash in a billionth of a second.

This trick preserved the perfect smoothness of the quantum layer. The electrons in it form a two-dimensional gas: they move only in a plane, like billiard balls on a perfectly flat table. Now that the road is unspoiled, physicists can run experiments they could only dream of before: for example, trapping electrons in clever quantum traps or creating devices sensitive to the slightest magnetic fields.

A mobility of 40 million cm²/(V·s) means an electron in such a material travels hundreds of micrometers without collisions, like an ant running several kilometers without ever tripping.

Scientists
Wolfgang PauliLeo EsakiKlaus von KlitzingLev LandauJohn BardeenShuji Nakamura
Concepts
electron mobility two dimensional electron gas gate voltage electronic devices gallium arsenide thermoelectric device solid state battery semimetal