Macroscale structural superlubricity at graphite/graphite and graphite/MoS2 interfaces. Credit: Minhao Han et al.

For the first time, physicists in China have virtually eliminated the friction felt between two surfaces at scales visible to the naked eye. In demonstrating "structural superlubricity," the team, led by Quanshui Zheng at Tsinghua University, have resolved a long-standing debate surrounding the possibility of the effect. Published in Physical Review Letters, the result could potentially lead to promising new advances in engineering.

What structural superlubricity promises

When two objects slide over each other, any roughness on their surfaces will almost inevitably resist the motion, creating the force of friction. Yet in 2004, physicists showed that friction can be virtually eliminated between two graphite surfaces, simply by rotating their respective molecular structures.

Named structural superlubricity (SSL), the effect is highly desired by engineers; in principle, allowing them to eliminate wear on both surfaces and minimize energy lost as waste heat.

However, "although SSL was discovered more than two decades ago, its realization has long been limited to micro- and nanoscale systems," explains co-author, Deli Peng. "Extending this phenomenon to macroscopic dimensions or realizing it under practical conditions such as macroscopic loads has remained elusive."

Why scaling up has proved difficult

According to some physicists, SSL on this scale would be impossible in real life due to effects including elasticity in the surfaces, and the presence of defects: small but unavoidable disruptions in molecular structure.

A key challenge in verifying the effect is that real graphite surfaces don’t exist as single crystalline arrangements. Instead, they are divided into "grains," which each host an orderly structure within themselves, but are oriented in random directions relative to each other. Since the sizes of these grains are limited to just tens of micrometers, SSL becomes impossible to maintain on larger scales.

The team’s single-crystal graphite solution

In their study, Zheng’s team addressed this problem using single-crystal graphite films grown specially using continuous epitaxy, which host millimeter-sized grains. They also combined this fabrication technique with a careful stacking approach, which allowed them to control the alignment of the graphite films more precisely.

"This approach enabled the construction of sub-millimeter-scale, nearly defect-free interfaces that maintain intimate atomic contact over macroscopic areas," Peng explains. "As a result, it overcomes the scaling barriers which constrain conventional experimental systems for observing structural superlubricity."

Macroscopic tests and surprising effects

For the first time, these innovations allowed the team to demonstrate SSL at the macroscale: maintaining virtually zero friction, even when they loaded the top surface with a broad range of weights, pushing the surfaces closer together.

In some cases, they even observed negative friction—where the effective resistive force decreased as the loads became heavier. In the most extreme conditions they considered, they estimated that an adult elephant standing on the top surface could be set into motion by a force equivalent to the weight of two eggs—or a light breeze.

"Similar behavior is also found at interfaces between graphite and molybdenum disulfide, indicating that macroscale structural superlubricity is a general phenomenon across flat layered materials," Peng describes.

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Publication details

Minhao Han et al. Anonymous, Observation of robust macroscale structural superlubricity, Physical Review Letters (2026). DOI: 10.1103/bv6j-q22p. On arXiv: DOI: 10.48550/arxiv.2601.00190

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Citation: Physicists achieve near-zero friction on macroscopic scales (2026, February 3) retrieved 3 February 2026 from https://phys.org/news/2026-02-physicists-friction-macroscopic-scales.html

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