Key Takeaways

• New research achieves record electron mobility in graphene, surpassing traditional GaAs-based systems.
• Two distinct methods were developed: one using twisted graphene layers and another involving proximity to a metallic gate.
• These advancements may significantly enhance applications in quantum technologies and high-speed electronics.

Graphene, a single layer of carbon atoms valued for its remarkable strength and conductivity, has struggled at cryogenic temperatures when compared to traditional gallium arsenide (GaAs) semiconductors. This limitation stems from electronic disorder caused by stray electric fields from defects, leading to charge density fluctuations that hinder electron mobility. Recent studies from the National University of Singapore (NUS) and The University of Manchester have introduced innovative strategies to overcome these challenges, achieving unprecedented levels of electron mobility that rival or exceed those of GaAs systems.

Twisted Graphene as a Shield

In a study published in Nature Communications on August 11, 2025, scientists explored a method to protect graphene from environmental disorder by stacking two graphene layers with a significant relative twist angle of 10° to 30°. This configuration decouples the electronic properties of the layers while maintaining a separation less than a nanometer. One of these layers can be doped to act as a metallic screen, significantly reducing charge inhomogeneity and scattering from electric field fluctuations. The result was an exceptional transport mobility of over 20 million cm²/Vs, with quantum mobility surpassing that of GaAs two-dimensional electron gases.

Proximity Screening for Enhanced Purity

In a subsequent study published in Nature on August 20, 2025, researchers led by Nobel Laureate Sir Andre Geim investigated a different approach by positioning graphene only a nanometer away from a metallic graphite gate, separated by an ultrathin layer of hexagonal boron nitride. This configuration dramatically enhanced Coulomb screening, resulting in an unprecedented Hall mobility exceeding 60 million cm²/Vs. This purity enabled phenomena like the Quantum Hall effect to manifest under much lower magnetic fields than typically required, marking a significant leap for graphene applications.

Complementary Advances for Ultra-Clean Graphene

Both studies offer complementary methods to tackle the issue of electronic disorder in graphene, providing valuable insights into enhancing its electronic performance. While the twisted layer method offers tunability, the proximity technique allows direct exploration of pristine graphene properties, yielding clean experimental platforms for further studies of quantum phenomena. Future research aims to adapt these methods for more complex graphene heterostructures, potentially expanding the understanding of many-body effects in quantum materials.

These breakthroughs not only advance the field of two-dimensional materials but also promise to improve the efficiency and performance of next-generation electronics and quantum sensing technologies. By enhancing the purity and mobility of graphene devices, researchers have unlocked new avenues for exploring quantum behaviors previously thought impossible.

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