Scientists create atomic scale, 2-D electronic kagome lattice

November 19, 2018 by Ben Longben Long, University of Wollongong
(Left to right) Dr Jincheng Zhuang, Dr Yi Du and Dr Zhi Li from the University of Wollongong's Institute for Superconducting and Electronic Materials. Credit: Paul Jones

Scientists from the University of Wollongong (UOW), working with colleagues at China's Beihang University, Nankai University, and Institute of Physics at Chinese Academy of Sciences, have successfully created an atomic scale, two-dimensional electronic kagome lattice with potential applications in electronics and quantum computing.

The is published in the November issue of Science Advances.

A kagome is named after a traditional Japanese woven bamboo pattern composed of interlaced triangles and hexagons.

The research team created the kagome lattice by layering and twisting two nanosheets of silicene. Silicene is a silicon-based, one-atom thick, Dirac fermion material with a hexagonal honeycomb structure, which can speed across at close to the speed of light.

When silicene is twisted into a kagome lattice, however, electrons become "trapped", circling around in the hexagons of the lattice.

Dr. Yi Du, who leads the Scanning Tunneling Microscopy (STM) group at UOW's Institute for Superconducting and Electronic Materials (ISEM) and Beihang-UOW Joint Research Centre, is the paper's corresponding author.

He said scientists have long been interested in making a 2-D kagome lattice because of the useful theoretical electronic properties such a structure would have.

"Theorists predicted a long time ago that if you put electrons into an electronic kagome lattice, destructive interferences would mean the electrons, instead of flowing through would instead turn around in a vortex and would become locked in the lattice. It is equivalent to someone losing their way in a maze and never getting out," Dr. Du said.

"The interesting point is that the electrons will be free only when the lattice is broken, when you create an edge. When an edge forms, electrons will move along with it without any electric resistance—it has very low resistance, so very low energy and electrons can move very fast, at the speed of light. This is of great importance for designing and developing low-energy-cost devices.

"Meanwhile, with a strong so-called spin-orbital coupling effect, novel quantum phenomena, such as frictional quantum Hall effect, are expected to happen at room temperature. This will pave a way for quantum devices in the future."

While the theoretical properties of an electronic kagome lattice made it of great interest to scientists, creating such a material has proved extremely challenging.

"For it to work as predicted, you have to make sure the lattice is constant, and that lengths of the lattice are comparable to the wavelengths of the electron, which rules a lot of materials out," Dr. Du said.

"It has to be a type of material on which the electron can only move on the surface. And you have to find something that is conductive, and also has a very strong spin-orbital coupling effect.

"There are not many elements in the world that have these properties."

One element that does is silicene. Dr. Du and his colleagues created their 2-D electronic kagome lattice by twisting together two layers of silicene. At a rotation angle of 21.8 degrees they formed a kagome lattice.

And when the researchers put electrons into it, it behaved as predicted.

"We observed all the phenomena predicted theoretically in our artificial kagome lattice in ," Dr. Du said.

The expected benefits of this breakthrough will be much more energy efficient electronic devices and faster, more powerful computers.

Explore further: 'Kagome metal': Physicists discover new quantum electronic material

More information: Zhi Li et al. Realization of flat band with possible nontrivial topology in electronic Kagome lattice, Science Advances (2018). DOI: 10.1126/sciadv.aau4511

Related Stories

Researchers developing 2-D materials similar to graphene

February 2, 2018

Chemists are working to synthesize the next generation of super materials for high-performance electronics, solar cells, photodetectors and quantum computers. While they have made progress with compound materials, they have ...

Topological protection in mechanical metamaterials

January 19, 2015

Researchers at Leiden University, the Netherlands, showed that certain crystal defects in mechanical metamaterials can harbour topologically protected motions. These mechanical states are analogues of protected electronic ...

The marriage of topology and magnetism in a Weyl system

August 6, 2018

Topology is a global aspect of materials, leading to fundamental new properties for compounds with large relativistic effects. The incorporation of heavy elements gives rise to non-trivial topological phases of matter, such ...

Recommended for you

Meteorite source in asteroid belt not a single debris field

February 17, 2019

A new study published online in Meteoritics and Planetary Science finds that our most common meteorites, those known as L chondrites, come from at least two different debris fields in the asteroid belt. The belt contains ...

Diagnosing 'art acne' in Georgia O'Keeffe's paintings

February 17, 2019

Even Georgia O'Keeffe noticed the pin-sized blisters bubbling on the surface of her paintings. For decades, conservationists and scholars assumed these tiny protrusions were grains of sand, kicked up from the New Mexico desert ...

Archaeologists discover Incan tomb in Peru

February 16, 2019

Peruvian archaeologists discovered an Incan tomb in the north of the country where an elite member of the pre-Columbian empire was buried, one of the investigators announced Friday.

Where is the universe hiding its missing mass?

February 15, 2019

Astronomers have spent decades looking for something that sounds like it would be hard to miss: about a third of the "normal" matter in the Universe. New results from NASA's Chandra X-ray Observatory may have helped them ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.