Polyyne electronic and vibrational properties under environmental interactions

Author(s)
Marius Wanko, Seymur Cahangirov, Lei Shi, Philip Rohringer, Zachary J. Lapin, Lukas Novotny, Paola Ayala, Thomas Pichler, Angel Rubio
Abstract

Recently the novel system of linear carbon chains inside double-walled carbon nanotubes has extended the length of sp1 hybridized carbon chains from 44 to thousands of atoms [Shi, Nat. Mater. 15, 634 (2016)1476-112210.1038/nmat4617]. The optoelectronic properties of these ultralong chains are poorly described by current theoretical models, which are based on short chain experimental data and assume a constant environment. As such, a physical understanding of the system in terms of charge transfer and van der Waals interactions is widely missing. We provide a reference for the intrinsic Raman frequency of polyynes in vacuo and explicitly describe the interactions between polyynes and carbon nanotubes. We find that van der Waals interactions strongly shift this frequency, which has been neither expected nor described for other intramolecular C-C stretching vibrations. As a consequence of charge transfer from the tube to the chain, the Raman response of long chains is qualitatively different from the known phonon dispersion of polymers close to the Γ point. Based on these findings we show how to correctly interpret the Raman data, considering the nanotube's properties. This is essential for its use as an analytical tool to optimize the growth process for future applications.

Organisation(s)
Electronic Properties of Materials
External organisation(s)
University of the Basque Country, Donostia International Physics Centre (DIPC), Bilkent University, Eidgenössische Technische Hochschule Zürich, Yachay Tech University, Max Planck Institute for the Structure and Dynamics of Matter
Journal
Physical Review B
Volume
94
No. of pages
6
ISSN
1098-0121
DOI
https://doi.org/10.1103/PhysRevB.94.195422
Publication date
11-2016
Peer reviewed
Yes
Austrian Fields of Science 2012
103015 Condensed matter
Keywords
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Portal url
https://ucrisportal.univie.ac.at/en/publications/127c7d13-ad0b-4fc1-8e33-3f24361786b1