Nav: Home

Moving silicon atoms in graphene with atomic precision

September 12, 2014

Richard Feynman famously posed the question in 1959: is it possible to see and manipulate individual atoms in materials? For a time his vision seemed more science fiction than science, but starting with groundbreaking experiments in the late 1980s and more recent developments in electron microscopy instrumentation it has become scientific reality. However, damage caused by the electron beam is often an issue in such experiments.

The present study focused on single-layer graphene with silicon atoms embedded into the lattice, previously created and studied by the collaborators from Manchester and Daresbury in the UK. Due to the larger size of silicon compared to carbon, these dopant atoms protrude out from the plane, which makes for interesting dynamics under the electron beam. The detailed simulations performed at the University of Vienna showed that the 60 kiloelectronvolt electrons that the cutting-edge Nion microscopes of both teams use for imaging the structure are not energetic enough to likely cause the outright ejection of atoms, in line with what had been observed.

Crucially, however, carbon atoms next to a silicon dopant are slightly less strongly bound, and can receive just enough of a kick to so that they almost escape from the lattice, but are recaptured due to an attractive interaction with the silicon atom. Meanwhile, the silicon relaxes into to the lattice position left empty by the impacted carbon atom, which thus lands back into the lattice on the opposite side from where it started. In effect, the silicon-carbon bond is inverted, which was directly seen by the microscopy teams. Analysing the experimental data of nearly 40 such jumps gave a probability that could be directly compared to the simulations, with remarkable agreement.

Besides being beautiful physics, the findings open promising possibilities for atomic-scale engineering: "What makes our results truly intriguing is that the bond flip is directional - the silicon moves to take the place of the carbon atom that was hit by a probe electron", explains lead author Toma Susi, physicist and FWF Lise Meitner Fellow at the University of Vienna. "This means that it should be possible to control the movement of one or more silicon atoms in the lattice with atomic precision. So perhaps we'll see a new kind of quantum corral or an university logo made of silicon atoms in graphene in the near future", he concludes.


Publication in Physical Review Letters:

Silicon-carbon bond inversions driven by 60 keV electrons in graphene: T. Susi, J. Kotakoski, D. Kepaptsoglou, C. Mangler, T.C. Lovejoy, O.L. Krivanek, R. Zan, U. Bangert, P. Ayala, J.C. Meyer & Q. Ramasse. Physical Review Letters, August 2014.
DOI: 10.1103/PhysRevLett.113.115501

Video Animation:

Visualisation of the silicon-carbon bond inversion

Video Abstract:

Toma Susi summarizes his research

Blog post Toma Susi (Mostly physics):

"Moving silicon atoms in graphene with atomic precision"

Scientific Contact:

Dr. Toma Susi
Tailored Hybrid Structures
Electronic Properties of Materials
Faculty of Physics
University of Vienna
1090 Vienna, Boltzmanngasse 5
T +43-1-4277-72614
M +43-664-527 3054

Press Contact:

Mag. Veronika Schallhart
Press Office
University of Vienna
1010 Vienna, Universitätsring 1
T +43-1-4277-175 30
M +43-664-602 77-175 30

The University of Vienna, founded in 1365, is one of the oldest and largest universities in Europe. About 9,500 employees, 6,700 of who are academic employees, work at 15 faculties and four centres. This makes the University of Vienna Austria's largest research and education institution. About 92,000 national and international students are currently enrolled at the University of Vienna. With more than 180 degree programmes, the University offers the most diverse range of studies in Austria. The University of Vienna is also a major provider of continuing education. In 2015, the Alma Mater Rudolphina Vindobonensis celebrates its 650th Anniversary.

University of Vienna
New chemical method could revolutionize graphene
University of Illinois at Chicago scientists have discovered a new chemical method that enables graphene to be incorporated into a wide range of applications while maintaining its ultra-fast electronics.
Searching beyond graphene for new wonder materials
Graphene, the two-dimensional, ultra lightweight and super-strong carbon film, has been hailed as a wonder material since its discovery in 2004.
New method of characterizing graphene
Scientists have developed a new method of characterizing graphene's properties without applying disruptive electrical contacts, allowing them to investigate both the resistance and quantum capacitance of graphene and other two-dimensional materials.
Chemically tailored graphene
Graphene is considered as one of the most promising new materials.
Beyond graphene: Advances make reduced graphene oxide electronics feasible
Researchers have developed a technique for converting positively charged (p-type) reduced graphene oxide (rGO) into negatively charged (n-type) rGO, creating a layered material that can be used to develop rGO-based transistors for use in electronic devices.
The Graphene 2017 Conference connects Barcelona with the international graphene-based industry
This prestigious Conference to be held at the Barcelona International Convention Centre (March 28-31) aims to bring together academia and industry to integrate new graphene technologies into practical applications.
Graphene from soybeans
A breakthrough by CSIRO-led scientists has made the world's strongest material more commercially viable, thanks to the humble soybean.
First use of graphene to detect cancer cells
By interfacing brain cells onto graphene, researchers at the University of Illinois at Chicago have shown they can differentiate a single hyperactive cancerous cell from a normal cell, pointing the way to developing a simple, noninvasive tool for early cancer diagnosis.
Development of graphene microwave photodetector
DGIST developed cryogenic microwave photodetector which is able to detect 100,000 times smaller light energy compared to the existing photedetectors.
Adding hydrogen to graphene
IBS researchers report a fundamental study of how graphene is hydrogenated.

Best Science Podcasts 2017

We have hand picked the best science podcasts for 2017. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.

Now Playing: Radiolab

Truth Trolls
Today, a third story of folks relentlessly searching for the truth. But this time, the truth seekers are an unlikely bunch... internet trolls.

Now Playing: TED Radio Hour

Rethinking School
For most of modern history, humans have placed smaller humans in institutions called schools. But what parts of this model still work? And what must change? This hour, TED speakers rethink education.TED speakers include teacher Tyler DeWitt, social entrepreneur Sal Khan, international education expert Andreas Schleicher, and educator Linda Cliatt-Wayman.