China has achieved a breakthrough in production of an ultra-pure form of silicon, a critical material needed to build silicon-based quantum computers, as Beijing accelerates its drive to cut reliance on foreign technology in strategic areas.

State-owned nuclear giant China National Nuclear Corporation (CNNC) said on Monday that one of its research institutes had successfully mass-produced a high-purity silicon-28 isotope with an isotopic abundance above 99.99 per cent. The achievement marked China’s first independent, large-scale production of the material, it said.

The breakthrough helps plug a long-standing gap in China’s quantum technology supply chain. Previously, production capabilities for the silicon-28 isotope were concentrated among a small group of overseas players in Russia, Europe and US-linked supply chains.

While standard silicon is the bedrock of smartphones and computer chips, quantum computers require an exceptionally pure variant.

Traditional computers process information using standard bits – represented as either a zero or one. Quantum computers, however, use qubits, which can exist as both a zero and a one simultaneously, allowing them to perform complex calculations at speeds exceeding supercomputers.

However, qubits are notoriously fragile. In natural silicon, magnetic interference – or “noise” – distorts the qubits, causing them to lose their quantum state and drop data.

In contrast, silicon-28 is a stable isotope. By purifying this variant, scientists can create an “ultra-quiet” environment, allowing qubits to remain stable for longer periods, which is vital for building functioning quantum computers.