One-way Superconductor Discovered!

By Aaryaa Padhyegurjar

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“If the 20th century was the century of semi-conductors, the 21st can become the century of the superconductor.”

Associate Professor Mazhar Ali and his research group at TU Delft have discovered one-way superconductivity in the absence of magnetic fields, which had been deemed impossible since its discovery in 1911 — until now. The research uses 2D quantum materials to pave the road for superconducting computing. Superconductors may speed up electronics by hundreds of times while consuming zero energy.

Many scientists, including Nobel Laureates, have struggled over the nature of superconductivity since it was discovered in 1911 by Dutch physicist Kamerlingh Onnes. Because a current in a superconductor flows across a wire with no resistance, stopping or even blocking it is difficult, let alone getting the current to go only one direction and not the other. The fact that Ali’s group’s principal researchers, Dr Heng Wu and Dr Yaojia Wang, were able to make superconducting one-directional – which is required for computing – is remarkable: it’s like inventing a particular sort of ice that has zero friction one way but insurmountable friction the other.

There are two benefits to using superconductors in electronics. Superconductors can make electronics hundreds of times faster, and incorporating them into our daily life would make IT far more environmentally friendly. If you spun a superconducting wire from here to the moon, no energy would be lost. According to the NWO, using superconductors instead of conventional semi-conductors might save up to 10% of total western energy reserves.

Mazhar Ali says, “Electrical conduction in semiconductors, like Si, can be one-way because of a fixed internal electric dipole, so a net built in potential they can have. The textbook example is the famous “pn junction”; where we slap together two semiconductors: one has extra electrons (-) and the other has extra holes (+). The separation of charge makes a net built in potential that an electron flying through the system will feel. This breaks symmetry and can result in “one-way” properties because forward vs backwards, for example, are no longer the same. There is a difference in going in the same direction as the dipole vs going against it; similar to if you were swimming with the river or swimming up the river.”

“Superconductors never had an analog of this one-directional idea without magnetic field; since they are more related to metals (i.e. conductors, as the name says) than semiconductors, which always conduct in both directions and don’t have any built in potential. Similarly, Josephson Junctions (JJs), which are sandwiches of two superconductors with non-superconducting, classical barrier materials in-between the superconductors, also haven’t had any particular symmetry-breaking mechanism that resulted in a difference between “forward” and “backwards”.


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