Layering transitions in superfluid helium adsorbed on a carbon nanotube mechanical resonator

Abstract

Helium is recognized as a model system for the study of phase transitions. Of particular interest is the superfluid phase in two dimensions. We report measurements on superfluid helium films adsorbed on the surface of a suspended carbon nanotube. We measure the mechanical vibrations of the nanotube to probe the adsorbed helium film. We demonstrate the formation of helium layers up to five atoms thickness. Upon increasing the vapour pressure, we observe layer-by-layer growth with discontinuities in both the number of adsorbed atoms and the speed of sound in the adsorbed film. These hitherto unobserved discontinuities point to a series of first-order layering transitions. Our results show that helium multilayers adsorbed on a nanotube are of unprecedented quality compared to previous works. They pave the way to new studies of quantized superfluid vortex dynamics on cylindrical surfaces, of the Berezinskii-Kosterlitz-Thouless phase transition in this new geometry, perhaps also to supersolidity in crystalline single layers as predicted in quantum Monte Carlo calculations.

10 pages, 3 figures

References in corpus (6)

• A tunable carbon nanotube electromechanical oscillator
• A Mechanical Mass Sensor with Yoctogram Resolution
• Nanotube mechanical resonators with quality factors of up to 5 million
• Phase diagram of 4He adsorbed on graphite
• Quantized superfluid vortex dynamics on cylindrical surfaces and planar annuli
• Atomic monolayer deposition on the surface of nanotube mechanical resonators

Cited by in corpus (11)

• Nanomechanical Resonators: Toward Atomic Scale
• Mesoscopic physics of nanomechanical systems
• Supersolidity in ultra-cold dipolar gases
• Mass sensing for the advanced fabrication of nanomechanical resonators
• Spatially Modulated Superfluid State in Two-Dimensional ${}^4$He Films
• Superfluid and supersolid phases of 4He on the second layer of graphite
• Superfluid Vortex Dynamics on Planar Sectors and Cones
• Supersolidity in the second layer of $para$-H${}_2$ adsorbed on graphite
• Fully suspended nano-beams for quantum fluids
• Phases of ${}^4$He and H${}_2$ adsorbed on a single carbon nanotube
• Nanomechanical vibrational response from electrical mixing measurements