Featured Research

from universities, journals, and other organizations

Observing the random diffusion of missing atoms in graphene

Date:
May 30, 2014
Source:
University of Vienna
Summary:
Imperfections in the regular atomic arrangements in crystals determine many of the properties of a material, and their diffusion is behind many microstructural changes in solids. However, imaging non-repeating atomic arrangements is difficult in conventional materials. Now, researchers have directly imaged the diffusion of a butterfly-shaped atomic defect in graphene, the recently discovered two-dimensional wonder material, over long image sequences.

Imperfections in the regular atomic arrangements in crystals determine many of the properties of a material, and their diffusion is behind many microstructural changes in solids. However, imaging non-repeating atomic arrangements is difficult in conventional materials. Now, researchers at the University of Vienna have directly imaged the diffusion of a butterfly-shaped atomic defect in graphene, the recently discovered two-dimensional wonder material, over long image sequences. The results are published in the journal Nature Communications.

Related Articles


Atomic scale defects are always present in materials. For conventional materials they are hidden inside a large number of perfectly arranged atoms, except for at the surface. However, the situation is different in the case of low-dimensional materials like graphene.

Graphene is a honeycomb-like arrangement of carbon atoms only one carbon atom thick. Since its discovery in 2004, several remarkable properties of this material have been measured. For example, it is stronger than diamond and conducts electricity better than copper, but is nevertheless transparent and remarkably flexible. Because all of the atoms in graphene are at the surface, individual atoms and any defects in the structure are directly visible in a high resolution electron microscope, but at the same time they easily interact with the environment.

The defect the researchers concentrated on in the recent study in Vienna is a double vacancy that forms when two atoms are missing from the crystal. In the most stable form of this defect the hexagons of the graphene lattice transform into an arrangement of four pentagons and four heptagons (five and seven-membered carbon rings, respectively) which looks like an atomic-scale butterfly. The study was carried out with the Nion UltraSTEM 100 microscope, which was installed in Vienna only last year. The combination of ultra high vacuum and low acceleration voltage of this device were key components for the success of the study. In earlier experiments, the defects have always rapidly evolved into more complex structures or converted back into crystalline graphene, thus preventing the continuous imaging of their diffusion over long periods of time. Now, the defects remained stable for a longer amount of time that allowed a statistical analysis of their motion.

The researchers used the electron beam of the microscope to transform the defect between different arrangements, which resulted in a migration of the structure from one image to the next. "It was remarkable to see for the first time how a defect transforms and migrates in the crystal over several minutes while we are watching it," says Dr. Jani Kotakoski, the lead author of the study. A careful analysis of the path of the defect revealed that the defect performed a random walk through the crystal. "Our study opens a new route for the direct study of defect migration and diffusion in low-dimensional materials, which can also lead to new insights into defect dynamics in solids in general," he concludes.


Story Source:

The above story is based on materials provided by University of Vienna. Note: Materials may be edited for content and length.


Journal Reference:

  1. Jani Kotakoski, Clemens Mangler, Jannik C. Meyer. Imaging atomic-level random walk of a point defect in graphene. Nature Communications, 2014; 5 DOI: 10.1038/ncomms4991

Cite This Page:

University of Vienna. "Observing the random diffusion of missing atoms in graphene." ScienceDaily. ScienceDaily, 30 May 2014. <www.sciencedaily.com/releases/2014/05/140530124333.htm>.
University of Vienna. (2014, May 30). Observing the random diffusion of missing atoms in graphene. ScienceDaily. Retrieved March 1, 2015 from www.sciencedaily.com/releases/2014/05/140530124333.htm
University of Vienna. "Observing the random diffusion of missing atoms in graphene." ScienceDaily. www.sciencedaily.com/releases/2014/05/140530124333.htm (accessed March 1, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Sunday, March 1, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Elon Musk's Hyperloop Moves Forward

Elon Musk's Hyperloop Moves Forward

Buzz60 (Feb. 27, 2015) Zipping around at 800-miles an hour is coming closer to reality in California. An entire town is being built around Elon Musk&apos;s Hyperloop concept and it wants you to stop in for a ride when it&apos;s ready. Brett Larson is on board. Video provided by Buzz60
Powered by NewsLook.com
Vibrating Bicycle Senses Traffic

Vibrating Bicycle Senses Traffic

Reuters - Innovations Video Online (Feb. 26, 2015) Dutch scientists have developed a smart bicycle that uses sensors, wireless technology and video to warn riders of traffic dangers. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
In Japan, Robot Dogs Are for Life -- And Death

In Japan, Robot Dogs Are for Life -- And Death

AFP (Feb. 25, 2015) Robot dogs are the perfect pet for some in Japan who go to repairmen-turned-vets when their pooch breaks down - while a full Buddhist funeral ceremony awaits those who don&apos;t make it. Duration: 02:40 Video provided by AFP
Powered by NewsLook.com
London Show Dissects History of Forensic Science

London Show Dissects History of Forensic Science

AFP (Feb. 25, 2015) Forensic science, which has fascinated generations with its unravelling of gruesome crime mysteries, is being put under the microscope in an exhibition of real criminal investigations in London. Duration: 00:53 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins