Info
Info
News Article

Visualising Atomic Scale Acoustic Waves In Nanostructures

News
Acoustic waves play many everyday roles; from communication between people to ultrasound imaging. Now the highest frequency
acoustic waves in materials, with nearly atomic scale wavelengths, promise to
be useful probes of nanostructures such as LED lights.
Lawrence Livermore National Laboratory scientists who discovered a new physical phenomenon that enables them to see high frequency waves by combining molecular dynamics simulations of shock waves with an experimental diagnostic, terahertz (THz) radiation. (The hertz is the base unit of frequency. One hertz simply means one cycle per second. A terahertz is 1012 hertz.).

The Livermore scientists performed computer simulations of the highest frequency acoustic waves forming spontaneously at the front of shock waves or generated by sub-picosecond pulse length lasers.

They discovered that, under some circumstances, when such a wave crosses an interface between two materials, tiny electric currents are generated at the interface. These currents produce electromagnetic radiation of THz frequencies that can be detected a few millimetres away from the interface. Part of the wave is effectively converted to electromagnetic radiation, which propagates out of the material where it can be measured.

Most molecular dynamics simulations of shock waves connect to experiments through electronic properties, such as optical reflectivity.

“But this new approach connects to the much lower frequency THz radiation produced by the individual atoms moving around in the shockwave,” said Evan Reed, lead author of a paper that appears in the July 7 promises to provide new information about shocked materials like the dynamics of crystals pushed to ultra-high strain rates.”

Using molecular dynamics simulations, the team, made up of Livermore's Reed and Michael Armstrong in collaboration with Los Alamos National Laboratory colleagues shows that the time-history of the wave can be determined with potentially sub picosecond, nearly atomic time and space resolution by measuring the electromagnetic field.

Reed and colleagues studied the effect for an interface between two thin films, which are used in LED (light-emitting diode) nanostructures, and are piezoelectric (electric currents that are generated when they are squeezed). Piezoelectric materials have been used for decades as arrival time gauges for shock-wave experiments but have been limited by electrical equipment that can only detect acoustic frequencies less than 10 gigathertz (GHz), precluding observation of the highest frequency acoustic waves. The new THz radiation technique can help improve the time resolution of such approaches.

The technique has other applications as well. It can be applied to determine the structure of many kinds of electronic devices that are constructed using thin film layered structures, such as field-effect transistors.

“The detection of high frequency acoustic waves also has been proposed for use in imaging of quantum dot nanostructures used in myriad optical devices, possibly including solar cells in the future,” Reed said. “The technology is not there yet for that application, but our work represents a step closer.”
Solar Power As Rental Offer Launched By Aggreko
Analysis Of UK Commercial Roof Space Shows Solar PV Film Can Achieve Net Zero Without Greenfield Sites
Sunstore Solar Launches WattGrid, A New Range Of Turnkey Off-grid Power Systems
Greencoat Renewables Announces First Transaction In Nordic Market
UK Green Tech Company Myenergi To Double Workforce By 2021
TLT Advises Innova Energy On £30m Refinancing Of 57 MW Solar Portfolio
NextEnergy Capital Acquires Its First Asset In Portugal 17.4MWp Solar PV Project
Low Carbon Develop UK’s Largest Community-owned Solar Park
FRV And Harmony Energy To Develop Second UK Utility Scale Battery Project
Oakapple Renewable Energy Appoint Stuart Gentry To Head Business Development
Tandem PV Devices Feel The Heat
Habitat Enerdy Enters Balancing Mechanism With Largest Battery
TLT Advises Santander On 30MW Flagship Battery Storage Project
Power Roll Trials Solar PV To Power Up Himalayan Villages
New Innovation Set To Change Renewable Energy Market
Sharp Launches New 440W Half-cut Cell PV Panel
SOLARWATT Links With Easy Roof To Provide Building-integrated PV For Better-looking Buildings And Smart EV Charging
Going Green In Lancashire – Hundreds Of Houses Installed With Solar Panels In Ground-breaking Project
FIMER Powers UK Largest Rooftop Solar Project
Sonnedix Named ESG Global Solar Power Generation Sector Leader By GRESB
Ingenious Invests In Electric Vehicle Charging Firm
UK'S Largest Battery Ready To Balance The Grid
Everoze Creates Skyray To Design And Engineer Great Solar PV Projects
The Smarter E South America Postponed To October 18-20, 2021
×
Search the news archive

To close this popup you can press escape or click the close icon.
Logo
×
Logo
×
Register - Step 1

You may choose to subscribe to the Smart Solar Magazine, the Smart Solar Newsletter, or both. You may also request additional information if required, before submitting your application.


Please subscribe me to:

 

You chose the industry type of "Other"

Please enter the industry that you work in:
Please enter the industry that you work in:
 
X
Info
X
Info
{taasPodcastNotification} Array
Live Event