Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Novel topological crystalline insulator shows mass appeal

30.08.2013
Experiments confirm defining characteristics of topological crystalline insulators

Disrupting the symmetrical structure of a solid-state topological crystalline insulator creates mass in previously mass-less electrons and imparts an unexpected level of control in this nascent class of materials, an international team of researchers reports in the current edition of Science Express.

The researchers not only confirmed several theoretical predictions about topological crystalline insulators (TCIs), but made a significant experimental leap forward that revealed even more details about the crystal structure and electronic behavior of these newly identified materials, according to Boston College Associate Professor of Physics Vidya Madhavan, one of the lead authors of the report.

The findings could pave the way for engineering the electronic properties of TCI surfaces towards novel functionalities at the nanoscale.

"There is a lot of rich physics here that's waiting to be explored," said Madhavan. "We've opened the door to better understanding topological crystalline insulators and the potential of these materials."

Confirmed within the past few years, topological insulators possess interiors that behave like insulators, blocking the flow of electrons. Yet externally, they contain conducting states where electrons can move freely across their surfaces. A few years ago, physicists first posited the existence of TCIs, a new class of topological materials where conducting surface electrons are theorized to obey fundamental quantum laws set by the crystalline structure of the interior.

Starting with a TCI consisting of lead and selenium, researchers sought to disrupt its structural symmetry by provoking, or doping, the material through the addition of tin, Madhavan said. The subsequent disruption had a dramatic effect on mass-less "Dirac" electrons that are present within the material and behave as relativistic particles. The manipulation added mass to some of these electrons, which took their places side-by-side with the Dirac electrons, a startling result in a solid-state material, Madhavan said.

The new massive electrons were measured topologically through scanning tunneling microscopy and electrically through spectroscopy, the researchers report.

The analysis revealed the Dirac point, which is the defining characteristic of the TCI, said Madhavan. Furthermore, the researchers found that varying the amount of tin imparted a measure of control over the material's properties, fulfilling yet another theoretical prediction.

Madhavan said the results confirmed the TCI's exotic band structure, a measure of the energy a surface electron may or may not possess within a solid. At the same time, the fundamental properties of the TCI remained accessible.

Moreover, observing and controlling Dirac electrons in TCIs paves the way for investigating relativistic physics in solid state systems: physics which was previously accessible only in the experiments of high-energy physics where particles are accelerated to speeds close to light.

In addition, the experiments revealed two distinct regimes of fermiology, an energy boundary used to make determinations about the properties of metals and semiconductors.

Along with Madhavan, the project team featured some of the leading researchers in condensed matter physics, including Boston College Assistant Professor of Physics Stephen Wilson, MIT Assistant Professor of Physics Liang Fu, Princeton University Professor of Physics M. Zahid Hasan, Northeastern University Professor of Physics Arun Bansil and National Taiwan University Researcher Fang Cheng Chou.

Ed Hayward | EurekAlert!
Further information:
http://www.bc.edu

More articles from Physics and Astronomy:

nachricht First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied Science

nachricht Nuclear physicists leap into quantum computing with first simulations of atomic nucleus
24.05.2018 | DOE/Oak Ridge National Laboratory

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

When corals eat plastics

24.05.2018 | Ecology, The Environment and Conservation

Surgery involving ultrasound energy found to treat high blood pressure

24.05.2018 | Medical Engineering

First chip-scale broadband optical system that can sense molecules in the mid-IR

24.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>