High-energy ions' movement affected by silicon crystal periodicity

March 22, 2018, Springer
High-energy ions' movement affected by silicon crystal periodicity
Simulated spatial and angular distributions for high-energy protons along a silicon axis. Credit: Springer

The thinner the silicon crystal, the better. Indeed, thinner crystals provide better ways to manipulate the trajectories of very high-energy ions in particle accelerators. Further applications include materials analysis, semiconductor doping and beam transport in large particle accelerators. All of these rely on our understanding of how positively-charged high-energy particles move through crystals.

This process, called ion channelling, is the focus of a new paper by Mallikarjuna Motapothula and Mark Breese working at the National University of Singapore. In a paper published in EPJ B, the authors study how the crystal periodicity affects the motion of ions whose belongs to a 1 to 2 MeV range, as they are transmitted through very thin crystals on the order of a few hundred nanometres, and how it impacts their angular distribution.

Channelling in crystals occurs when the transverse energy of incident ions is less than the maximum potential energy associated with an atom row or a crystal plane. The authors study the trajectories of high-energy ions, which pass through several radial rings of atomic strings before exiting the thin crystal. Each ring may focus, steer or scatter the channelled ions in the transverse direction.

What is so interesting about this work is that it relies on an advanced process of fabricating much thinner crystals than was previously possible, reaching 55 nanometres. This, in turn, makes it possible to observe much more sensitive and fine angular structures in the distribution of transmitted ions.

Thanks to such advanced materials, the authors found that several previously observed but poorly understood phenomena related to ion channelling can now be explained. These phenomena are related to the fact that ions approach the crystal nuclei within a certain range of distances and are scattered through an angle large enough for them to interact with several adjacent atoms before exiting the thin crystal with a distinctive angular distribution.

Explore further: Discovery creates a new paradigm for creating materials from crystals

More information: Mallikarjuna Rao Motapothula et al, A study of small impact parameter ion channeling effects in thin crystals, The European Physical Journal B (2018). DOI: 10.1140/epjb/e2018-80580-4

Related Stories

Meteorite impact on a nano scale

August 29, 2016

A meteorite impacting the earth under a grazing angle of incidence can do a lot of damage; it may travel a long way, carving a trench into the ground until it finally penetrates the surface. The impact site may be vaporized, ...

Recommended for you

New insights into magnetic quantum effects in solids

January 23, 2019

Using a new computational method, an international collaboration has succeeded for the first time in systematically investigating magnetic quantum effects in the well-known 3-D pyrochlore Heisenberg model. The surprising ...

Rapid and continuous 3-D printing with light

January 22, 2019

Three-dimensional (3-D) printing, also known as additive manufacturing (AM), can transform a material layer by layer to build an object of interest. 3-D printing is not a new concept, since stereolithography printers have ...

Scientists discover new quantum spin liquid

January 22, 2019

An international research team led by the University of Liverpool and McMaster University has made a significant breakthrough in the search for new states of matter.

Researchers capture an image of negative capacitance in action

January 21, 2019

For the first time ever, an international team of researchers imaged the microscopic state of negative capacitance. This novel result provides researchers with fundamental, atomistic insight into the physics of negative capacitance, ...

Toward ultrafast spintronics

January 21, 2019

Electronics have advanced through continuous improvements in microprocessor technology since the 1960s. However, this process of refinement is projected to stall in the near future due to constraints imposed by the laws of ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.