Quantum processors need classical control electronics, but silicon controllers generate heat and demand power that force them to sit far from the qubits they manage, creating a wiring bottleneck that worsens as qubit counts rise. A team in the Department of Electrical and Computer Engineering at HKU, working through the Centre for Advanced Semiconductors and Integrated Circuits, has built neuromorphic hardware that functions at cryogenic temperatures and could therefore be placed much closer.
The mechanism relies on negative differential resistance generated and controlled in standard silicon carbide transistors. Below 2 kelvin the devices display an S-shaped resistance characteristic driven by impact ionisation of electron donors, an effect intrinsic to the material and reportedly repeatable across manufacturing batches. A single transistor reproduced the energy-efficient spiking behaviour of a biological neuron at temperatures as low as 10 millikelvin, and the neurons can be cascaded into larger networks.
Manufacturability is unusually favourable for a device of this kind. Silicon carbide is already in volume production for electric vehicles and power grid equipment, so the chips could be fabricated in existing foundries on 300 millimetre wafers rather than requiring a bespoke process developed from scratch. That matters for a field in which many cryogenic device demonstrations depend on materials or fabrication steps with no industrial pathway behind them. The work was published in Nature Communications.
Beyond quantum control, where reduced thermal load could assist error correction and real-time operation, the team highlights deep-space missions in which electronics must survive extreme cold without heaters. Both applications share a requirement that conventional complementary logic handles badly: computation that remains efficient when the environment itself is near absolute zero, rather than computation that must be insulated from it.