Nav: Home

How a tetrahedral substance can be more symmetrical than a spherical atom: A new type of symmetry

September 14, 2018

Scientists at Tokyo Institute of Technology have theoretically demonstrated that special tetrahedron nanostructures composed of certain metals have a higher degree of symmetry than the geometrical symmetry of spherical atoms. Nanomaterials with unique and unprecedented electrical and magnetic properties arising from this symmetry will be developed and used for next-generation electronic devices.

Studying symmetry, one of the most fundamental concepts in physics and chemistry, can facilitate a deeper understanding of the laws shaping our universe.

Atoms naturally have the highest degree of geometrical symmetry, corresponding to the spherical symmetry. An interesting property often arising from symmetry is a high degree of degeneracy--a characteristic of quantum energy levels wherein a given energy level can correspond simultaneously to two or more different states in a quantum system. Degeneracy gives rise to properties including high conductivity and magnetism, which could be exploited to create novel electronic materials. Unfortunately, given the limitations of geometrical symmetry, no substance is known to have a higher degree of degeneracy than spherical atoms (Fig. 1). But what if substances could have a different type of symmetry leading to a higher degree of degeneracy? How could such a symmetry be explained?

Researchers from Tokyo Institute of Technology, including Prof. Kimihisa Yamamoto, set out to demonstrate the existence of metals with such types of symmetry. The team inferred that special inflated tetrahedron structures made of specific metal atoms, such as zinc and magnesium, may have a special type of symmetry arising not from geometrical properties but from the dynamic characteristics of the system. "We have demonstrated that realistic magnesium, zinc, and cadmium clusters having a specific tetrahedral framework possess anomalous higher-fold degeneracies than spherical symmetry," explains Yamamoto.

The team used a tight-binding model analysis, validated with density functional theory calculations, to identify the general condition regarding the bonding interactions between atoms (the "transfer integrals") giving rise to the predicted dynamical symmetry. "Surprisingly, the degeneracy condition can be represented as an elegant square-root mathematical sequence involving the ratios of the transfer integrals (Fig. 2). It is also impressive that this sequence has already been discovered by Theodorus in the ancient Greece, independently of materials science," says Yamamoto.

This research demonstrated that nanomaterials with a degree of symmetry higher than that of spherical atoms can be realized. The super-degenerate quantum states resulting from this dynamical symmetry could be exploited in multiple ways, such as designing new materials with unprecedented conductivity or magnetic properties, heralding the next generation of electronic devices.
-end-


Tokyo Institute of Technology

Related Nanomaterials Articles:

Development of low-dimensional nanomaterials could revolutionize future technologies
Javier Vela, scientist at the US Department of Energy's Ames Laboratory, believes improvements in computer processors, TV displays and solar cells will come from scientific advancements in the synthesis of low-dimensional nanomaterials.
Researchers create first significant examples of optical crystallography for nanomaterials
Researchers at the University of Illinois at Urbana-Champaign have developed a novel way to determine crystal type based on optics -- by identifying the unique ways in which these crystals absorb light.
Researchers create anticancer nanomaterials by simulating underwater volcanic conditions
Researchers at Aalto University, Finland, have developed anticancer nanomaterials by simulating the volcano-induced dynamic chemistry of the deep ocean.
Utilizing tumor suppressor proteins to shape nanomaterials
A new method combining tumor suppressor protein p53 and biomineralization peptide BMPep successfully created hexagonal silver nanoplates, suggesting an efficient strategy for controlling the nanostructure of inorganic materials.
Direct radiolabeling of nanomaterials
Positron emission tomography plays a pivotal role for monitoring the distribution and accumulation of radiolabeled nanomaterials in living subjects.
New solution for making 2-D nanomaterials
Two-dimensional (2-D) nanomaterials have been made by dissolving layered materials in liquids, according to new UCL-led research.
Nanomaterials for neurology: State-of-the-art
Despite the numerous challenges associated with the application of nanotechnology in neuroscience, it promises to have a significant impact on our understanding of how the nervous system works, how it fails in disease, and the development of earlier and less-invasive diagnostic procedures so we can intervene in the preclinical stage of neurological disease before extensive neurological damage has taken place.
Can we find more benign nanomaterials?
University of Iowa chemist Sara Mason has won a grant to access a supercomputer network funded by the US National Science Foundation.
Application-safe and environmentally friendly development and use of nanomaterials
Thus BfR researchers have found out that pure silver nanoparticles are, following simulated digestion in the stomach and intestine, absorbed in much lower quantities than particles which are digested together with food components.
Notre Dame researchers find transition point in semiconductor nanomaterials
Collaborative research at Notre Dame has demonstrated that electronic interactions play a significant role in the dimensional crossover of semiconductor nanomaterials.

Related Nanomaterials Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Don't Fear Math
Why do many of us hate, even fear math? Why are we convinced we're bad at it? This hour, TED speakers explore the myths we tell ourselves and how changing our approach can unlock the beauty of math. Guests include budgeting specialist Phylecia Jones, mathematician and educator Dan Finkel, math teacher Eddie Woo, educator Masha Gershman, and radio personality and eternal math nerd Adam Spencer.
Now Playing: Science for the People

#518 With Genetic Knowledge Comes the Need for Counselling
This week we delve into genetic testing - for yourself and your future children. We speak with Jane Tiller, lawyer and genetic counsellor, about genetic tests that are available to the public, and what to do with the results of these tests. And we talk with Noam Shomron, associate professor at the Sackler School of Medicine at Tel Aviv University, about technological advancements his lab has made in the genetic testing of fetuses.