Researchers uncover a novel mechanical bistability in carbon nanotubes
A study published in Nano Letters demonstrates the existence of two stable states in carbon nanotubes—tiny tubes of carbon just a few nanometers in diameter—and reveals that the system switches between these mechanical states due to intrinsic fluctuations.
Scientists from the Polytechnic University of Marche, Michigan State University, TU Delft, and Dr. Wei Yang and Prof. Adrian Bachtold from ICFO have discovered a previously unobserved form of bistability in a mechanical resonator based on a carbon nanotube. This bistability, reported on Nano Letters, manifests as two distinct stable states: a quiet state where the nanotube remains nearly motionless, and a second state characterized by large, sustained oscillations. Unlike typical bistability observed in mechanical resonators, this new type was not triggered by sweeping an external control parameter.
Switching between the two states was achieved simply by applying a constant voltage across the nanotube’s ends. What makes this bistability unique is that the large oscillatory state emerges spontaneously through the system’s intrinsic fluctuations, causing transitions between states without external modulation. In fact, without noise, the bistability would disappear, and the oscillatory state would remain hidden.
The team precisely measured how long the nanotube stayed in each state, confirming that both states are equally stable. They also developed a minimal theoretical model to explain the origin of this bistability and the mechanisms driving it.
This work advances our understanding of complex nonlinear dynamics in nanomechanical oscillators and could have important implications for nanotechnology applications that rely on precise control of mechanical vibrations, such as ultra-sensitive sensors and nanoscale actuators.
Reference:
P. Belardinelli, W. Yang, A. Bachtold, M. I. Dykman, F. Alijani, Hidden Vibrational Bistability Revealed by Intrinsic Fluctuations of a Carbon Nanotube, Nano Lett. (2025).
DOI: https://doi.org/10.1021/acs.nanolett.4c06618
Acknowledgements:
Financial support was provided from the European Union’s research and innovation programme under ERC starting grant no. 802093, ERC consolidator grant no. 101125458, and ERC advanced grant no. 692876. M.I.D. acknowledges partial support from the U.S. Defense Advanced Research Projects Agency (Grant No. HR0011-23-2-004) and from the Gordon and Betty Moore Foundation Award GBMF12214 (doi.org/10.37807/GBMF12214). P.B. acknowledges partial support from the European Union’s NextGenerationEU programme, in the framework of PRIN 2022, project DIMIN. A.B. acknowledges MICINN Grant No. RTI2018-097953-B-I00 and PID2021- 122813OB-I00, AGAUR (Grant No. 2017SGR1664), the Fondo Europeo de Desarrollo, the Spanish Ministry of Economy and Competitiveness through Quantum CCAA, TED2021-129654B-I00, EUR2022-134050, and CEX2019- 000910-S [MCIN/AEI/10.13039/501100011033], MCIN with funding from European Union NextGenerationEU (PRTR-C17.I1) and Generalitat de Catalunya, CERCA, Fundacio Cellex, Fundacio Mir-Puig.