Physicists at Loughborough University are making great strides towards creating the next generation of scanning tunnelling microscopes (STM) through studying Weyl semimetals – topological materials identified in 2015 as having novel properties, such allowing electrons to move freely without resistance.
Due to the infancy of the Weyl semimetal discovery, made in 2015 at Princeton University, USA, little research has been done to identify their suitability for real world applications.
However, last month, Professor Feo Kusmartsev, Dr Romilly Hills and Dr Anna Kusmartseva took the first step and published a paper outlining a series of newly observed Weyl characteristics, and theoretically investigated a range of scientific devices which could be built using the semimetals.
Their proposals included the design of a new microscope ‘super lens’ capable of high precision imaging down to an atom’s width – one Ångström, or 0.1 nanometers.
A strand of human DNA is 2.5 nanometers in diameter.
Prof Kusmartsev said the race was now on to make the ‘negative refraction super lens’.
“The next step is absolutely clear.” He said. “We have to make the two and three layered structures we have described.
“First, to demonstrate the negative refraction effect.
“Then, to use each of these three-layered structures as the tip of a scanning tunnelling microscope and find which of them is most optimal for imaging.
“The improving the imaging technique to uncover many mysteries of nature – for example, learning more about hydrogen bonding would shed light on many issues, in particular how a life formed on Earth and how the fission of biological cells happens."
At present, scientists can only image crystals or their atomic structure, for example a series of spots identified as atoms, but it is not yet possible to see the structure of individual molecules and atoms.
“We cannot see chemical bonds," said Prof Kusmartsev. "Or how these bonds form, or the molecules, or any structure.
“The new negative refraction super lens will provide a really strong breakthrough in this research.”
Scientists and engineers are available to advance current technology using Weyl materials due to the way the electrons within the semimetals behave.
They contain electrons with no mass – the same as light particles (photons).
Without mass, electrons can move across large spaces without resistance.
They also come with other added benefits – which are extra charge and a negative refractive index.
Negative refraction allows much greater focusing because it does not scatter light in the same way as a normal (positive) refraction lens.