Quantum sieving of hydrogen isotopes
22 March 2018
A team of researchers from the University of Manchester in collaboration with Prof. Peeters from the CMT group at UAntwerpen, have discovered that the naturally occurring gaps between individual layers of two-dimensional materials can be used as a sieve to separate different atoms and their isotopes.
Writing in Nature Nanotechnology (S. Hu, et al, Nature Nanotech. 2018, doi: 10.1038/s41565-018-0088-0), the scientists show that hydrogen and deuterium –two hydrogen isotopes – can be separated if pushed through miniscule spaces in between atomically thin materials such as hexagonal boron nitride or molybdenum disulphide.
Similar to graphene these materials can exist in a two-dimensional (2D) layer and exhibit unique properties due to their physical structure. Stacking different 2D crystals can allow the creation of bespoke multifunctional materials tailored to specific purposes.
The Manchester team led by Sir Andre Geim reported that some 2D layered crystals can be used as the smallest possible mesh to create sub-atomic sieves. At first glance, there is no space left between the atomically thin layers of the crystals because they are densely stacked on top of each other.
However the team discovered tiny gaps did exist by successfully forcing hydrogen isotopes to pass through the miniscule cavities. By doing so, the team managed to separate these isotopes at room temperature, exploiting an exotic phenomenon, known as quantum sieving.
Isotope separation is typically a highly energy intensive operation which is used in nuclear, medical and research sectors. Hydrogen and deuterium – isotopes of hydrogen – have the same size if considered as classical particles but are rather different in size as waves if their quantum nature is taken into account.
Deuterium has a shorter wavelength than hydrogen, which allows it to pass more easily through tiny capillaries and become separated from hydrogen. This sieving mechanism, known as quantum sieving, exploits an attribute known as the 'particle-wave duality of matter' – a well-known physics phenomenon. However, extremely low temperatures are typically required to observe it.
Read the full article at Phys.org
Credit: University of Manchester