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Atomic silicon circuitry

Our main building block is the silicon dangling bond on a H-terminated silicon surface, which we have shown acts as a quantum dot.  Precise assemblies of such dots can be created to form artificial molecules.  Such ensembles can have custom optical properties, can serve as circuit elements for quantum-dot cellular automata, and, we suspect, can play a role in quantum computing. 


Our work has pushed the boundaries of atom-scale fabrication, imaging techniques, and dynamic charge sensing of single surface atoms and of single dopants.  See Publications for a list of our recent work.  

Because the atomic silicon quantum dot (ASiQD) is so small - perhaps the ultimate small dot - it has very widely spaced electronic energy levels.  This has multiple important ramifications.  The Quantum Dot Cellular Automata scheme due to Lent, Porod and coworkers, for example, is now set to flourish.  While the QCA architecture has been highly developed theoretically and proven experimentally, it has until now languished because the relatively large size, and commensurately small energy level spacing of available dots required extreme cryogenic conditions.  Our patented ASiQDs now allow room temperature operation, while simultaneously eliminating practical issues related to clocking and wiring.  Spin-off company Quantum Silicon Incorporated, QSi, is tackling the challenges of interfacing the new atom-sized circuitry to conventional CMOS and to make first working prototypes.


Within the QCA scheme, the binary states “1” and “0” are encoded in the position of electric charge. Variants exist but most commonly the basic cell consists of a rectangular quantum dot ensemble occupied by 2 electrons.  Multiple cells couple and naturally mimic the electron configuration of nearest-neighbour cells. In general, cell-cell interactions must be described quantum mechanically but to a good approximation 

they are described simply by electrostatic interactions. Electrons freely tunnel among the quantum dots in a cell, while electron tunneling between cells does not occur.  Within a cell, two classically equivalent states exist, each with electrons placed on a diagonal.

Design and test atomic circuits now using SiQAD 

See Bob's TED Talk on Atom Scale Manufacturing here

2. Most compact data storage.JPG

a) Scanning tunneling microscope (STM) images of a rewritable 8-bit memory constructed from dangling bonds (DBs) and b) an STM image of an expanded 192-bit memory, storing 24 simplified notes (converted into binary) of the popular Mario video game theme song.


Interested in visiting, collaborating, or working with us? Drop us a line

Robert Wolkow - Group Supervisor


Department of Physics - Condensed Matter

3-182 CCIS 11455 Saskatchewan Drive NW

Edmonton, AB T6G 2H5

Office hours are by appointment only

The University of Alberta is committed to cultivating an institutional culture that values, supports, and promotes equity, human rights, respect, and accountability among faculty, staff, and students.

Postdoctoral Positions

Currently, consideration will only be given to candidates with expert-level ultra high vacuum scanning tunneling microscopy skills. 

Salaries are currently around $50,000. Some travel assistance may be available. Medical and Dental coverage is provided.

The research group includes people with backgrounds in physics, chemical physics, engineering and chemistry. In our group we enjoy a pleasant and dynamic atmosphere where one can become immersed in exciting science.

Our group’s laboratories are extremely well-equipped (See Our Facilities).

Edmonton, Alberta is a wonderful place to live offering the advantages of a big city; ballet (truly excellent and a favourite of mine), opera, symphony, extensive theatre, galleries - while still having a safe, small town feeling. A wide range of popular outdoor activities are also available ranging from bicycling to camping and kayaking, and skiing. The spectacular Rocky Mountains are only a 3.5 hours away by car. 
Postdoctoral appointments ordinarily run for two years and may be extended for a third year. Applicants must have a strong mechanical aptitude and hands-on experience with ultra high vacuum techniques. A PhD in physics or chemistry (chemical physics oriented) is required. 

Graduate Students

Graduate physics students can study with me by becoming a graduate student at the University of Alberta Physics Department where I am a professor. A co-supervised theory student position is also available in cooperation with Professor Hong Guo at McGill University (where I am an adjunct prof.) Co-supervised chemistry graduate students are welcomed as well.

Summer Students

Summer students are welcome to join us. Interested students should make contact through their university's undergraduate summer job placement services or by sending an email to me at Summer students should have a demonstrable mechanical aptitude (could you fix a flat tire on your bike when you were a kid?, have you built an electronic circuit?, can you program?). Emails should provide anecdotes which describe such experience, a resume, and an unofficial transcript.

Contact us



AVS Nanotechnology Recognition Award

October 21, 2020

Dr. Wolkow was honoured with one of the world’s premier nanotechnology awards—AVS Nanoscale Science and Technology Division Nanotechnology Recognition Award. 

Deep learning-guided surface characterization for autonomous fabrication

May 13, 2020

A blog post written by PhD student, Jeremy Croshaw, about beyond CMOS devices. 


January 16, 2020

Quantum Silicon Inc.: A new generation of computing circuits that are tiny, fast and cool.

30 years of moving atoms: How scanning probe microscopes revolutionized nanoscience

November 12, 2019

Published in c&en. Our contribution on automated STM-based patterning systems is highlighted under "Giving Electrons a Bump".


June 15, 2019

Bob talks about Atom Scale Manufacturing and its role in creating the ultimate green technology. 

Binary atomic silicon logic

December 13, 2018

Exciting new paper in Nature Electronics. Here we demonstrate rudimentary circuit elements through the patterning of dangling bonds on a hydrogen-terminated silicon surface.

Want to design and test atomic circuits now? Check out SiQAD by collaborator Walus Lab

APS Physics Highlight

November 01, 2019

"A research team led by Robert Wolkow at the University of Alberta in Canada has now demonstrated that they can place and detect a single electron with atomic resolution using an all-mechanical approach."

Physics World news story about our paper in Phys. Rev. Lett.

October 29, 2018

"We are now able to play with single charges (electrons) in atomically-defined structures of our own design for the first time"

Tiny technology leads to big data breakthrough for Edmonton scientists

July 25, 2018

CBC article with Roshan Achal on mastering the art of writing computer memory at the atomic level, at new technology which exceeds the capabilities of current hard drives by 1,000 times. 


July 04, 2018

Professor Moriarty on the paper he wishes his group had published (which was published by our Postdoc Moe Rashidi!). Machine Learning has allowed nano-scientists to Autofocus their equipment for the first time - at an atomic level.

Scientists are using AI to painstakingly assemble single atoms

May 23, 2018

Article in Wired about our grand plan to use a scanning probe microscope to make new types of chips that could usher in a new era of computing


July 06, 2017

We created a maple leaf 10,000 times smaller than the diameter of a human hair!

Faculty of Science - Student Highlight

February 14, 2017

The ultimate green technology - creating computers that use one thousand times less energy

Alberta Primetime

February 10, 2017

Interview with Shawna Randolph discussing our most recent disovery

University of Alberta researchers solves puzzle that baffled researchers for decades

January 09, 2017

Our team's research on negative differential resistance (NDR) solves a decades old scientific mystery and could be used to create cheaper, smaller and faster computers

Edmonton researchers' tiny discovery may revolutionize computers

November 01, 2016

Our team, together with collaborators at the Max Planck Institute in Hamburg, have developed a way to created atomic switches for electricity nearly 100 times smaller than the smallest switches, or transistors, on the market today

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