Regular Article

The potentials and challenges of electron microscopy in the study of atomic chains^*

¹ Institut de Physique et Chimie des Matériaux, Université de Strasbourg, CNRS, UMR 7504, 67034 Strasbourg, France
² Nanoscale and Microscale Research Centre, University of Nottingham, Nottingham NG7 2RD, UK
³ International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-8565, Japan

^a e-mail: florian.banhart@ipcms.unistra.fr

Received: 22 August 2016
Revised: 27 January 2017
Accepted: 3 April 2017
Published online: 5 May 2017

Abstract

The article is a brief review on the potential of transmission electron microscopy (TEM) in the investigation of atom chains which are the paradigm of a strictly one-dimensional material. After the progress of TEM in the study of new two-dimensional materials, microscopy of free-standing one-dimensional structures is a new challenge with its inherent potentials and difficulties. In-situ experiments in the TEM allowed, for the first time, to generate isolated atomic chains consisting of metals, carbon or boron nitride. Besides having delivered a solid proof for the existence of atomic chains, in-situ TEM studies also enabled us to measure the electrical properties of these fundamental linear structures. While ballistic quantum conductivity is observed in chains of metal atoms, electrical transport in chains of sp¹-hybridized carbon is limited by resonant states and reflections at the contacts. Although substantial progress has been made in recent TEM studies of atom chains, fundamental questions have to be answered, concerning the structural stability of the chains, bonding states at the contacts, and the suitability for applications in nanotechnology.