Nav: Home

The discovery of Majorana fermion

March 17, 2017

The detection of Majorana fermion is one of the hotspots in the study of condensed matter recently. The research group in Shanghai Jiao Tong University (SJTU) achieved great breakthrough in the detection of Majorana fermion in the artificial topological superconductor, which is the heterostructure of a normal superconductor and a topological insulator. Majorana fermion was successfully detected in this system.

A review article on the research of Majorana fermion in the artificial topological superconductor was recently published in Science China Physics, Mechanics & Astronomy (SCPMA), 60, 057401, 2017. In this article, a series of significant experimental results from Prof. Jin-Feng Jia's group in SJTU, and their co-workers were discussed.

Majorana fermion is an exotic particle, whose anti-particle is exactly the same with itself. In condensed matter, Majorana fermion exists as a quasi-particle excitation in topological superconductors. It obeys non-Abelian statistics and thus can be used in fault-tolerant topological quantum computation, which greatly enhances the application ability of quantum computer.

No topological superconductor in nature has been confirmed yet. Physicists however built a heterostructure of superconductor and topological insulator. In the heterostructure, the topological surface states acquire the superconductivity from the superconducting substrate via proximity effect and become topological superconductor. Applied magnetic field, Majorana fermion will existed in the excited vortex core on the surface of the heterostructure.

There exist two major difficulties in the research of Majorana fermion in artificial topological superconductor. One is to find proper materials for the heterostructure. The other is to detect the Majorana fermion. In 2012, the group in SJTU successfully grown epitaxial topological insulator Bi2Se3 films on top of superconductor NbSe2 which built a milestone of in this research. In the following years, they built the heterostructure Bi2Te3/NbSe2 and detected Majorana fermions in such system via STM.

Majorana fermion is an electronic state that lies at zero energy. In the vortex core, there exist other low energy states that are unrepeatable under current STM energy resolution. This is the major hinder in the detection of Majorana fermion. However, researchers found that the spatial distribution of Majorana fermion is significantly different from other excitation states in the vortex core. By carefully analysis the spatial distribution of the excitation states in the vortex core of the heterostructure, they found solid evidences of the existence of Majorana fermion for the first time. Moreover, Majorana fermion has exotic spin properties that give spin-selective Andreev reflection process. Via a spin-polarized STM, this process was also detected in the heterostructure, which became not only another evidence of Majorana fermion's existence but also a potential method to control Majorana fermion in this system. Once Majorana fermion can be controlled, the topological quantum computation will be more realistic.
See the article: Hao-Hua Sun and Jin-Feng Jia, Majorana zero mode in the vortex of an artificial topological superconductor, Science China-Physics Mechanics Astronomy, 60, 057401, 2017.

Science China Press

Related Superconductor Articles:

New understanding of superconductor's 'normal' state may help solve longstanding puzzle
experiments done at the University of Illinois at Urbana-Champaign in the Madhavan and Abbamonte laboratories, in collaboration with researchers at six institutions in the US, Canada, United Kingdom, and Japan, have shed new light on the electronic properties of this material at temperatures 4°K above Tc.
Group works toward devising topological superconductor
A team led by Cornell physics associate professor Eun-Ah Kim has proposed a topological superconductor made from an ultrathin transition metal dichalcogenide that is a step toward quantum computing.
Seaweed: From superfood to superconductor
Seaweed, the edible algae with a long history in some Asian cuisines, and which has also become part of the Western foodie culture, could turn out to be an essential ingredient in another trend: the development of more sustainable ways to power our devices.
The discovery of Majorana fermion
Majorana fermion can serve as the building block of fault tolerant topological quantum computing.
Superconductivity with two-fold symmetry -- new evidence for topological superconductor SrxBi2Se3
Topological superconductivity is the quantum condensate of paired electrons with an odd parity of the pairing function.
Graphene's sleeping superconductivity awakens
The intrinsic ability of graphene to superconduct (or carry an electrical current with no resistance) has been activated for the first time.
Quantum obstacle course changes material from superconductor to insulator
Researchers from Brown University have shown a way to break superconductivity by disrupting the coherence of superconducting Cooper pairs.
DOE funds advanced manufacturing of superconductor wire for next generation machines
The US Department of Energy Monday announced a $4.5 million grant to Venkat Selvamanickam, MD Anderson Chair Professor of Mechanical Engineering at the University of Houston, to boost the advanced manufacturing of high-performance superconductor wires for next generation electric machines.
Physicists spell 'AV' by manipulating Abrikosov vortices
A nanophotonics group lead by Prof. Brahim Lounis of the University of Bordeaux and including scientists from MIPT has performed a unique experiment involving the optical manipulation of individual Abrikosov vortices in a superconductor.
Scientists find static 'stripes' of electrical charge in copper-oxide superconductor
Understanding the electronic ordering in copper-oxide superconductors could help scientists find the 'recipe' for raising the temperature at which current can flow through these materials without energy loss.

Related Superconductor Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".