Graphene insulators pave way for quantum computing

23 December 2013
By Tereza Pultarova
Mobile version
Share |
Researchers have changed properties of graphene making it act as a topological insulator

Researchers have changed properties of graphene making it act as a topological insulator [Credit:MIT]

American researchers have discovered how to make graphene capable of filtering electrons according to their ‘spins’, opening new possibilities for future quantum computing.

Taking advantage of the so-called Hall Effect, the team from the Massachusetts Institute of Technology (MIT), led by professors Pablo Jarillo-Herrero and Ray Ashoori managed to alter the behaviour of the wonder material making electrons with positive spins to move clockwise around the conductive edge of a graphene sheet and those with negative spins to circle anti-clockwise. The study has been published in the latest issue of the journal Nature.

“We created an unusual kind of conductor along the edge, virtually a one-dimensional wire,” said Andrea Young, a Pappalardo Postdoctoral Fellow in MIT’s physics department, explaining that segregation of electrons according to their spins is a normal feature of topological insulators. However, graphene is not normally a topological insulator.

“We’re getting the same effect in a very different material system,” Young said.

Under normal circumstanced sheets of graphene behave as normal conductors. When voltage is applied, the electric current flows throughout the two-dimensional flake. If a graphene flake is, in addition, subject to a magnetic field perpendicular to the flake itself, its behaviour changes with current flowing only along the edge and the bulk becoming an insulator. In such a situation, electric current flows only in one direction, either clockwise or anti-clockwise, depending on the orientation of the magnetic field. This phenomenon is known as the quantum Hall effect.

In the newest experiment, the MIT researchers discovered that if a second powerful magnetic field is applied, this time in the same plane as the graphene flake, electrons with different spins start moving in different directions.

“We can turn these edge states on and off,” Young said, explaining that such capability would allow creating graphene circuits and transistors, possibly paving the way for future quantum computers.

The experiment was conducted using a magnetic field of about 35 Tesla - ten times stronger than an MRI scanner - at temperatures about 0.3 degrees Celsius above absolute zero.

According to Jarillo-Herrero, the Mitsui Career Development Associate Professor of Physics at MIT, such behaviour in graphene has previously been predicted but never actually observed.

Latest Issue

E&T cover image 1607

"As the dust settles after the referendum result, we consider what happens next. We also look forward to an international summer of sport."

E&T jobs

  • Design Delivery Leader, Palace of Westminster Restoration & Renewal (R&R) - Engineering Lead

    House of Commons
    • City of Westminster, London (Greater)
    • Circa £65,000 (There may be more for an exceptional candidate)

    You will lead on a number of engineering infrastructure and associated workstreams under direction from the Deputy Director

    • Recruiter: House of Commons

    Apply for this job

  • Senior Engineer, Network Equipment

    Energy Networks Association
    • Westminster
    • £49-58k per annum, dependent on experience

    Manage issues and working groups relating to all types of equipment and assets used on the UK Transmission and Distribution Networks.

    • Recruiter: Energy Networks Association

    Apply for this job

  • Programme Manager, Network Resilience

    Energy Networks Association
    • Westminster
    • Competitive salary, dependent on experience

    Co-ordinate the network resilience, emergency planning and the Single Electricity Number (SEN) work in the ENA Engineering team.

    • Recruiter: Energy Networks Association

    Apply for this job

  • Assistant Professor (Tenure Track) of Smart Building Solutions

    Premium job

    ETH Zurich
    • Zurich, Canton of Zürich (CH)

    The successful candidate is expected to develop a strong and visible research programme in the area of control and diagnostics of building systems

    • Recruiter: ETH Zurich

    Apply for this job

  • Process Controls Leader

    Premium job

    Phillips 66
    • Humber Refinery, South Killingholme, North Lincolnshire DN40 3DW
    • £60k - 75k plus extensive Compensation and benefits package, dependent upon experience

    Experienced Process Control Leader providing leadership and technical support for Oil Refinery. Extensive Compensation and benefits package.

    • Recruiter: Phillips 66

    Apply for this job

  • Regional Technical Support Manager

    Premium job

    • Warwick, Warwickshire

    You will be required to lead the regional Customer Services strategy and resources to maximise Customer satisfaction.

    • Recruiter: Siemens

    Apply for this job

  • Communications Engineer

    BAE Systems
    • England, Hampshire, Portsmouth
    • Negotiable

    Communications Engineer Would you like to play a key role supporting the UK's Maritime Communications Infrastructure? We currently have a vacancy for a Communications Engineer at our site in Portsmouth. As a Communications Engineer, you will be carrying o

    • Recruiter: BAE Systems

    Apply for this job

  • MetOp-SG Receiver Project Manager

    Science and Technology Facilities Council (STFC)
    • STFC Rutherford Appleton Laboratory, Harwell, Oxfordshire
    • £37,213 - £50,926 (depending on experience)

    Project Manager to oversee the development, production and test of spaceflight components and integrated receiver systems

    • Recruiter: Science and Technology Facilities Council (STFC)

    Apply for this job

  • Financial Controller

    • Stevenage
    • Competitive Salary & Benefits

    An opportunity has arisen to manage a diverse range of financial controlling activities within the Equipment Team (ET) and newly Centres of Excellence (CofEx) function...

    • Recruiter: MBDA

    Apply for this job

  • Weapon System Product Support Manager

    • Stevenage
    • Competitive Salary & Benefits

    The Opportunity An opportunity has arisen within MBDA?s Customer Support & Services organisation for a strong competent leader to deliver a key Weapon capability primarily...

    • Recruiter: MBDA

    Apply for this job

More jobs ▶


Choose the way you would like to access the latest news and developments in your field.

Subscribe to E&T