Transition from three to two dimensions increases conduction

July 7, 2015, Moscow Institute of Physics and Technology
The crystal structure of Nb3SiTe6. Credit: © J. Hu et al/ Nature Physics

Scientists from the MIPT Department of Molecular and Chemical Physics have for the first time described the behavior of electrons in a previously unstudied analogue of graphene, two-dimensional niobium telluride, and, in the process, uncovered the nature of two-dimensionality effects on conducting properties. These findings will help in the creation of future flat and flexible electronic devices.

In recent decades, physicists have actively studied so-called two-dimensional . Andrei Geim and Konstantin Novoselov received the Nobel Prize for their research on graphene, the most well-known among them. The properties of such materials, which can be described as "sheets" with a thickness of a few atoms, strongly differ from their three-dimensional analogues. For example, graphene is transparent, conducts current better than copper and has good thermal conductivity. Scientists believe that other types of two-dimensional materials may possess even more exotic properties.

A group of scientists from Russia and the USA, including Pavel Sorokin and Liubov Antipina from MIPT, recently conducted research on the properties of the crystals of one such material,Nb3SiTe6, a compound of niobium telluride. In their structure, the crystals resemble sandwiches with a thickness of three atoms (around 4 angstroms): a layer of tellurium, a layer of niobium mixed with silicon atoms and then another layer of tellurium. This substance belongs to a class of materials known as dichalcogenides, which many scientists view as promising two-dimensional semiconductors.

The scientists synthesized Nb3SiTe6 crystals in a laboratory at Tulane University (New Orleans). They then separated them into two-dimensional layers, taking samples for further analysis by , X-ray crystal analysis and other methods. The goal of the researchers was to investigate electron-phonon interaction changes in two-dimensional substances.

A picture of a membrane sample of the niobium telluride compound Nb3SiTe6. Credit: © J. Huetal/ Nature Physics

Quasi particles, quanta of crystal lattice oscillations, are called phonons. Physicists introduced the concept of phonons because it helped simplify the description of processes in crystals, and tracking of electron-phonon interaction is fundamentally important for description of the different conducting in matter.

"We developed a theory that predicts that electron-phonon interaction is suppressed due to dimensional effects in two-dimensional material. In other words, these materials obstruct the flow of electrons to a lesser extent," says Pavel Sorokin, a co-author of the study, doctor of physical and mathematical sciences, and lecturer at the MIPT Section of the Physics and Chemistry of Nanostructures (DMCP).

American colleagues confirmed this prediction in related experiments. "They conducted measurements where the same effectwas observed. Our calculations allowed the ruling out of other explanations; we managed to prove that changes in electron-phonon interaction occur specifically because of the two-dimensionality of the membrane," Sorokin adds.

Full details of the research discussed above can be found in an article published in the journal Nature Physics.

Explore further: Electrons move like light in three-dimensional solid

More information: "Enhanced electron coherence in atomically thin Nb3SiTe6." Nature Physics 11, 471–476 (2015) DOI: 10.1038/nphys3321

Related Stories

Electrons move like light in three-dimensional solid

April 22, 2015

Electrons were observed to travel in a solid at an unusually high velocity, which remained the same independent of the electron energy. This anomalous light-like behavior is found in special two-dimensional materials, such ...

Bilayer graphene is another step toward graphene electronics

August 11, 2011

The Nobel Prize winning scientists Professor Andre Geim and Professor Kostya Novoselov have taken a huge step forward in studying the wonder material graphene and revealing its exciting electronic properties for future electronic ...

Physicists fine-tune control of agile exotic materials

June 23, 2015

Physicists have found a way to control the length and strength of waves of atomic motion called polaritons that have promising potential uses such as fine-scale imaging and the transmission of information within tight spaces. ...

Graphene meets heat waves

March 6, 2015

EPFL researchers have shed new light on the fundamental mechanisms of heat dissipation in graphene and other two-dimensional materials. They have shown that heat can propagate as a wave over very long distances. This is key ...

Recommended for you

Sculpting stable structures in pure liquids

February 21, 2019

Oscillating flow and light pulses can be used to create reconfigurable architecture in liquid crystals. Materials scientists can carefully engineer concerted microfluidic flows and localized optothermal fields to achieve ...

How to freeze heat conduction

February 21, 2019

Physicists have discovered a new effect, which makes it possible to create excellent thermal insulators which conduct electricity. Such materials can be used to convert waste heat into electrical energy.

Water is more homogeneous than expected

February 21, 2019

In order to explain the known anomalies in water, some researchers assume that water consists of a mixture of two phases, even under ambient conditions. However, new X-ray spectroscopic analyses at BESSY II, ESRF and Swiss ...

Correlated nucleons may solve 35-year-old mystery

February 20, 2019

A careful re-analysis of data taken at the Department of Energy's Thomas Jefferson National Accelerator Facility has revealed a possible link between correlated protons and neutrons in the nucleus and a 35-year-old mystery. ...

0 comments

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.