Chinese breakthrough paves way for production of graphene-based quantum chips

Chinese scientists have made a significant breakthrough in the development of graphene-based quantum chips, a crucial component for next-generation quantum computers. According to a study published in the prestigious journal Science on July 23, researchers from Peking University have successfully fabricated rhombohedral graphene – a form of graphene that has been notoriously difficult to produce at scale in the past. This new development opens up possibilities for creating stable and scalable quantum devices.

Rhombohedral graphene, a unique stacking arrangement of graphene layers, exhibits remarkable properties such as superconductivity and the quantum anomalous Hall effect. These properties make it an ideal platform for exploring quantum effects and for building topological qubits, a type of quantum computing unit that is largely immune to noise. However, the instability and rarity of this stacking arrangement have hindered its practical application until now.

Led by Liu Kaihui, the research team overcame this challenge by developing a growth template with a step on its edge. This design allowed graphene layers to stack layer by layer, similar to building blocks, with the geometric boundary imposed by the step locking in a stable interlayer shift. Through theoretical screening and repeated experiments, the researchers achieved a high-purity form of rhombohedral graphene with dimensions up to 160 micrometres by 80 micrometres and a thickness of up to 120 nanometres.

The team's approach represents a paradigm shift in stacking-sequence engineering in quantum materials, paving the way for their scalable applications in future quantum science and technologies. By utilizing a copper-nickel alloy on an aluminium oxide step as a catalyst and epitaxial template, the researchers were able to induce rhombohedral graphene formation at high temperatures, resulting in a material that is over 99% pure.

This breakthrough could revolutionize the field of quantum computing, offering an excellent platform for studying quantum phenomena and providing an abundant and easy-to-process material for future research. While the full extent of rhombohedral graphene's potential remains to be seen, the material's abundance and ease of processing make it a promising candidate for advancing next-generation quantum devices.