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Updated: Jun 23, 2026

Resonance Raman Spectroscopy of Extreme Nanowires and Other 1D Systems
Published on: April 28, 2016
Dielectric properties of water inside single-walled carbon nanotubes
Fuminori Mikami1, Kazuyuki Matsuda, Hiromichi Kataura
1Department of Physics, Faculty of Science, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo 192-0397, Japan.
Abstract:
In this paper, we report novel ferroelectric properties of a new form of ice inside single-walled carbon nanotubes (SWCNTs). These are called "ice nanotubes" (ice NTs) and they consist of polygonal water rings stacked one-dimensionally along the SWCNT axis. We performed molecular dynamics (MD) calculations for the ice NTs under an external electric field and in a temperature range between 100 and 350 K. It is revealed that ice NTs show stepwise polarization with a significant hysteresis loop as a function of the external field strength. In particular, pentagonal and heptagonal ice NTs are found to be the world's smallest ferroelectrics with spontaneous polarization of around 1 microC/cm(2). The n-gonal ice NT, where n = 5, 6, or 7, has (n + 1)-polarized structures with different polarizations. These findings suggest potential applications of SWCNTs encapsulating dielectric materials for the fabrication of the smallest ferroelectric devices. Experimental evidence for the presence of ice NTs inside SWCNTs is also discussed in great detail.
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