Infrared phonon anomaly of one-dimensional metallic peanut-shaped C60 polymer

Abstract

The infrared (IR) phonon properties of one-dimensional (1D) metallic peanut-shaped C60 polymers, which exhibit an energy gap below 60 K [Y. Toda et al., Appl. Phys. Lett. 92, 094102 (2008)] that is similar to the Peierls transition of quasi-1D metallic materials, have been examined in the temperature range of 30–300 K by high-resolution in-situ IR spectroscopy. We observed an IR phonon anomaly in which two new IR modes appear at 50 K and become increasingly anomalous with decreasing temperature in a similar manner as phase phonons associated with charge density waves in quasi-1D condensates.

High-resolution transmission electron microscopic and electron diffraction studies of C60 single crystal films before and after electron-beam irradiation

“…Although we already obtained several facts [8,9] indicating the 1D metallic peanut-shaped C 60 polymer as well as Tomonaga-Luttinger liquid behavior [3], we have not obtained the experimental results directly supporting the 1D geometric structure so far. In the present study, we have examined the geometric structure of the C 60 polymer single crystal (SC) film formed by EB irradiation of a C 60 SC film, using HR transmission electron microscope (TEM) and electron diffraction (ED) in combination with ED simulations of 1D C 60 polymer SC models.…”

Unifying explanation for carrier relaxation anomaly in gapped systems

“…Now, we apply the proposed theory to photo-excited carrier relaxation in quasi one-dimensional C 60 polymers. It was previously observed in experiments [24] that the C 60 polymers undergo the CDW transition [25] at T c = 60K, forming a well-defined energy gap at the Fermi level. This result implied the possibility of τ expdivergence at 60K; nevertheless, optical pump-probe investigations [18] of the C 60 polymers revealed a monotonic variation in τ exp near T c , whose origin has yet to be clarified.…”

Immobilization of CO2 at Room Temperature Using the Specific Sub‐NM Space of 1D Uneven‐Structured C60 Polymer Film

“…We have investigated 1D uneven‐structured (peanut‐shaped) C 60 polymer ( Figure b) by electron‐beam (EB) irradiation of C 60 films (Figure 1a) under ultrahigh vacuum (UHV) conditions. [ 9–16 ] The polymer film has a hexagonal‐closed pack (hcp) structure (the left panel of Figure 1b), [ 12 ] resulting in formation of sub‐nm spaces with a sizes of ≈0.3 and 0.6 nm periodically arranged (the right panel of Figure 1b). In addition, the 1D polymer exhibits physical properties arising from 1D metal [ 13–16 ] and a high heat‐resistance [ 17 ] comparable to that of commercially available polyimides.…”