Phase Transitions of Adsorbed Atoms on the Surface of a Carbon Nanotube

Abstract

Phase transitions of adsorbed atoms and molecules on two-dimensional substrates are well explored, but similar transitions in the one-dimensional limit have been more difficult to study experimentally. Suspended carbon nanotubes can act as nanoscale resonators with remarkable electromechanical properties and the ability to detect adsorption at the level of single atoms. We used single-walled carbon nanotube resonators to study the phase behavior of adsorbed argon and krypton atoms as well as their coupling to the substrate electrons. By monitoring the resonance frequency in the presence of gases, we observed the formation of monolayers on the cylindrical surface, phase transitions within them, and simultaneous modification of the electrical conductance.

Structures, Energetics, and Dynamics of Helium Adsorbed on Isolated Fullerene Ions

“…At the other end of the spectrum that started with graphitic surfaces are helium layers physisorbed on isolated nanotubes [10], planar aromatic molecules [11], and fullerenes [12,13]. The dimensionality of their surfaces changes from 0D or 1D to 2D as the size of the system increases.…”

“…The dimensionality of their surfaces changes from 0D or 1D to 2D as the size of the system increases. The resonance frequency of a single-walled suspended nanotube has been measured to monitor phase transitions in an adsorbate of argon and xenon [10]; the coupling of helium to gas-phase anthracene, phtalocyanine, and other planar aromatic molecules has been probed by high-resolution spectroscopy (see references in [11]). …”

4He adsorbed outside a single carbon nanotube

“…3, we examine how the phase diagrams evolved when the tube radii increased. There, from top to bottom, we show the energy per particle of the different adsorbed phases on the (8,8), (10,10), and (12,12) tubes. As indicated above, for the (8,8) nanotube the ground state corresponds to an incommensurate solid.…”

“…(1), and curved counterparts of the registered √ 3 × √ 3 phases have been considered. 10 Structures with helium atoms regularly distributed on circumferences (or rows) whose defining planes were perpendicular to the main axis (z) of the cylinders were also studied. Those solids are defined by the number of absorbed atoms on each circle and are named accordingly.…”

Spatial mapping of multimode Brownian motions in high-frequency silicon carbide microdisk resonators

“…This study provides deterministic information for identifying the mode sequences in multimode disk resonators, along with key characteristics of the multiple modes that are required for multimode signal processing and sensing 40 . The SiC multimode microdisks will help advance recent attempts towards multimodal sensing of individual adsorbing particles and surface adsorbates phase changes and dynamic fluctuations 24,25,41,42 , with dramatically enhanced capturing surfaces and multi-modalities. The unique transparency of SiC and its near-zero absorption of wide range in visible also make the SiC-on-SiO 2 microdisks an ideal platform for multimodal sensing in liquids 43,44 .…”