A team of researchers from Osaka University, TU Wien, Nanyang Technological University, Rice University, University of Alberta and Southern Illinois University-Carbondale comes closer to unraveling the physics of quasiparticles in carbon nanotubes.
Carbon nanotubes (CNTs), a model one-dimensional (1D) material made up entirely of carbon atoms, have attracted considerable attention ever since their discovery because of the unique properties arising from quantum confinement effects.
CNTs have been labeled as one of the materials for next-generation optoelectronic devices. Critical towards this advancement is understanding how quasiparticles - theoretical particles used to describe observable phenomena in solids - behave and interact with each other in a 1D system.
This requires a fundamentally different model compared to a conventional 3D material like silicon as a consequence of the reduced dimensionality in CNTs.
"It was difficult to develop a terahertz radiation device with an external high electric field in a specific direction to CNT," says corresponding author Masayoshi Tonouchi.
By combining different experimental techniques, the team was able to directly probe the creation of free charge carriers in CNTs at different time scales after photoexcitation.
Very complex interactions that involve different quasiparticles occur after the initial photoexcitation. These processes change over time, and being able to probe one of the quasiparticles makes it easier to understand the whole process.
Together with state-of-the-art simulations, the team was able to identify two key mechanisms that explain their data and helped them develop a detailed microscopic model describing quasiparticle interactions in a strong electric field in CNTs.
"We proposed a model in which electron-hole bound quasiparticles excited in the high energy E22 exciton band diverge to the low energy band and play a role in ultrafast electrical conduction. This model successfully explained the experimental facts and led to the clarification of the physical properties of CNTs."
Their results shed light on a number of long-standing issues in CNT ultrafast dynamics, moving us closer towards the realization of advanced optoelectronics based on CNTs and other low-dimensional materials.
The article, "Terahertz Excitonics in Carbon Nanotubes: Exciton Autoionization and Multiplication," was published in ACS Nano Letters at DOI: https:/
About Osaka University
Osaka University was founded in 1931 as one of the seven imperial universities of Japan and now has expanded to one of Japan's leading comprehensive universities. The University has now embarked on open research revolution from a position as Japan's most innovative university and among the most innovative institutions in the world according to Reuters 2015 Top 100 Innovative Universities and the Nature Index Innovation 2017. The university's ability to innovate from the stage of fundamental research through the creation of useful technology with economic impact stems from its broad disciplinary spectrum.
Saori Obayashi | EurekAlert!
Atoms at the photo shoot
03.08.2020 | Humboldt-Universität zu Berlin
Collisions in the solar system: Bayreuth researchers explain the origins of stony-iron meteorites
03.08.2020 | Universität Bayreuth
Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...
“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.
Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...
An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.
Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...
Although no life has been detected on the Martian surface, a new study from astrophysicist and research scientist at the Center for Space Science at NYU Abu...
New approach creates synthetic layered magnets with unprecedented level of control over their magnetic properties
The magnetic properties of a chromium halide can be tuned by manipulating the non-magnetic atoms in the material, a team, led by Boston College researchers,...
23.07.2020 | Event News
21.07.2020 | Event News
07.07.2020 | Event News
04.08.2020 | Life Sciences
04.08.2020 | Medical Engineering
04.08.2020 | Ecology, The Environment and Conservation