Computer Simulations Show How Light Pulses Can Create Channels that Conduct Electricity with No Resistance in Atomically Thin Semiconductors
Theoretical physicists at the Department of Energy’s SLAC National Accelerator Laboratory used computer simulations to show how special light pulses could create robust channels where electricity flows without resistance in an atomically thin semiconductor.
If this approach is confirmed by experiments, it could open the door to a new way of creating and controlling this desirable property in a wider range of materials than is possible today.
The result was published in Nature Communications.
Over the past decade, understanding how to create this exotic type of material – known as “topologically protected” because its surface states are impervious to minor distortions – has been a hot research topic in materials science. The best-known examples are topological insulators, which conduct electricity with no resistance in confined channels along their edges or surfaces, but not through their interiors.
SLAC and Stanford University researchers have been at the forefront of discovering such materials and investigating their properties, which could have future applications in microelectronic circuits and devices. This year’s Nobel Prize in Physics was awarded to three scientists who first suggested the possibility of topologically protected material properties.
Previous theoretical studies had looked at how light might induce topologically protected phenomena in graphene, a sheet of pure carbon just one atom thick. Unfortunately, it would take an impractically high light energy and intensity to induce that effect in graphene. In this study, SLAC researchers focused on tungsten disulfide and related compounds, which form sheets just one molecule thick and are intrinsically semiconducting
The researchers simulated experiments in which pulses of circularly polarized light, in the red to near-infrared wavelength range, hit a single layer of tungsten disulfide. The results showed that during the time the material was illuminated, its electrons organized themselves in a manner fundamentally different from graphene, creating new paths with absolutely no electrical resistance along the sample’s edges.
To account for the fluctuating interactions between light waves and electrons, the researchers employed a periodically time-varying frame of reference that had roots dating back to the 1880s and French mathematician Gaston Floquet. The approach clearly showed that lower-energy light, to which the material would seem transparent, would create topologically protected, no-resistance edge paths in the tungsten disulfide monolayer.
Moreover, the simulation showed that unwanted heating of the material that would disrupt the paths could be avoided by tuning the light energy to be slightly less than the most-efficient “resonant” energy.
“We are the first to connect first-principles material models with light-induced topologically protected states while mitigating excess material heating,” said Martin Claassen, a Stanford graduate student working at SLAC and lead author of the technical paper.
The researchers are in discussions with other research groups that could lead to experiments that test their theoretical predictions in real materials.
Receive an email update when we add a new TOPOLOGICAL MATERIALS article.
The Latest on: Topological materials
via Google News
The Latest on: Topological materials
- Science BREAKTHROUGH: A new state of matter has just been discoveredon August 16, 2019 at 11:20 am
This new topological state can be manipulated in ways that could ... However, there is no natural host material for these particles, also known as Majorana fermions. READ MORE: Scientists probe ...
- New state of matter may lead to better electronicson August 16, 2019 at 12:20 am
"This new topological state can be manipulated in ways that could ... However, there is no natural host material for these particles, also known as Majorana fermions. As a result, researchers have ...
- Newfound superconductor material could be the 'silicon of quantum computers'on August 15, 2019 at 11:56 am
Most spin-triplet SCs are predicted to be "topological" SCs as well, with a highly useful property in which the superconductivity would occur on the surface of the material and would remain ...
- Researchers propose new topological phase of atomic matter hosting 'photonic skyrmions'on August 14, 2019 at 10:54 am
"We showed there can exist a new topological phase of matter where light flows only on the edge of the atomic material but not inside it. There might exist some very special materials with this ...
- Topological photonics offers route to qubit-to-qubit communicationon August 13, 2019 at 6:34 am
In condensed matter, meanwhile, topological materials display similar geometries on the molecular scale, which gives them diverse mechanical and electrical properties. Recent studies have explored how ...
- Active matter goes chaoticon August 10, 2019 at 1:55 am
A fluorescence microscope image of the active matter studied. Image courtesy: Amanda Tan, University of California, Merced Topological defects in the structure of materials known as active nematics ...
- Study Reveals Hidden Topological Insulator States in Bismuth Crystalson August 7, 2019 at 8:12 am
has concentrated on a class of materials called “topological insulators.” A crystal of bismuth has a staircase-like appearance because of the repeating honeycomb-like structure of its atoms.
- Researchers uncover hidden topological insulator states in bismuth crystalson August 7, 2019 at 5:09 am
... materials for computers and other electronic devices has focused on a group of materials known as "topological insulators" that have a special property of conducting electricity on the edge ...
- Researchers at Forschungszentrum Jülich develop novel process for structuring quantum materialson August 6, 2019 at 9:06 pm
Jülich, 29 July 2019 – Implementing quantum materials in computer chips provides access to fundamentally new technologies. To build high-performance quantum computers, for example, topological ...
via Bing News