Tag Archives: Hiroshi Onodera

20 bromine atoms, a Swiss cross and room temperature

I haven’t featured a teeny, tiny object in quite a while so here’s a Swiss cross composed of 20 bromine atoms,

20 bromine atoms positioned on a sodium chloride surface using the tip of an atomic force microscope at room temperature, creating a Swiss cross with the size of 5.6nm. The structure is stable at room temperature and was achieved by exchanging chlorine with bromine atoms. (Fig: Department of Physics, University of Basel)

20 bromine atoms positioned on a sodium chloride surface using the tip of an atomic force microscope at room temperature, creating a Swiss cross with the size of 5.6nm. The structure is stable at room temperature and was achieved by exchanging chlorine with bromine atoms. (Fig: Department of Physics, University of Basel)

A July 15, 2014 news item on ScienceDaily features the research illustrated by the image,

The manipulation of atoms has reached a new level: Together with teams from Finland and Japan, physicists from the University of Basel were able to place 20 single atoms on a fully insulated surface at room temperature to form the smallest “Swiss cross,” thus taking a big step towards next generation atomic-scale storage devices. …

A July 15, 2014 Universität Basel press release (also on EurekAlert), which originated the news item, explains why this is a breakthrough,

Ever since the 1990s, physicists have been able to directly control surface structures by moving and positioning single atoms to certain atomic sites. A number of atomic manipulations have previously been demonstrated both on conducting or semi-conducting surfaces mainly under very low temperatures. However, the fabrication of artificial structures on an insulator at room temperature is still a long-standing challenge and previous attempts were uncontrollable and did not deliver the desired results.

In this study, an international team of researchers around Shigeki Kawai and Ernst Meyer from the Department of Physics at the University of Basel presents the first successful systematic atomic manipulation on an insulating surface at room temperatures. Using the tip of an atomic force microscope, they placed single bromine atoms on a sodium chloride surface to construct the shape of the Swiss cross. The tiny cross is made of 20 bromine atoms and was created by exchanging chlorine with bromine atoms. It measures only 5.6 nanometers square and represents the largest number of atomic manipulations ever achieved at room temperature.

Together with theoretical calculations the scientists were able to identify the novel manipulation mechanisms to fabricate unique structures at the atomic scale. The study thus shows how systematic atomic manipulation at room temperature is now possible and represents an important step towards the fabrication of a new generation of electromechanical systems, advanced atomic-scale data storage devices and logic circuits.

Here’s a link to and citation for the paper,

Atom manipulation on an insulating surface at room temperature by Shigeki Kawai, Adam S. Foster, Filippo Federici Canova, Hiroshi Onodera, Shin-ichi Kitamura, & Ernst Meyer. Nature Communications 5, Article number: 4403 doi:10.1038/ncomms5403 Published 15 July 2014

This article is behind a paywall but a free preview is available via ReadCube Access.

The bromine/Swiss cross accomplishment brings to mind Donald M. Eigler and Erhard K. Schweizer of IBM and their spelling of the company name with single xenon atoms in 1989. Here’s what Malcolm W. Browne had to say about it in his April 5, 1990 New York Times article,

Hiram Maxim, the inventor of the machine gun, used to demonstrate his marksmanship by firing patterns of bullets into walls to spell out the initials of potential customers. In a similar vein, I.B.M. announced yesterday that its scientists had spelled out the company’s initials by dragging single atoms into the desired pattern on the surface of a crystal of nickel.

One result of I.B.M.’s tour de force was the cover photograph of the British journal Nature today. In a letter published by the journal, Dr. Donald M. Eigler and Dr. Erhard K. Schweizer of the I.B.M. Almaden Research Center at San Jose, Calif., reported that using an instrument that can discern individual atoms, they had positioned single atoms of xenon into various patterns, including the letters I.B.M.

Browne offers a good description of how a scanning tunneling microscope and the process of moving atoms one atom at a time in the rest of his article.