A group of physicists at the Institute of Physics II have, for the first time, seen a particularly exotic electron behaviour in real space. Electrons usually move almost freely through three-dimensional space. However, when they are forced to move in only one dimension – i.e. along a chain of atoms – the electrons’ properties seem to split up. They normally have both a ‘spin’ – a quantum mechanical angular momentum – and a charge. In one dimension however, they stop behaving like normal electrons due to their strong interaction with each other. Instead, they divide into two types of quasi-particle that carry either the spin or the charge only. Until now, this phenomenon could only be shown indirectly by physicists’ experiments. Recently, an international team lead by Professor Dr Thomas Michely has created one-dimensional wires, in which they could locally observe this rare behaviour of trapped electrons for the first time, using a scanning tunnelling microscope. With this new find the limits of the Tomonaga-Luttinger Liquid theory – which explains this strange phenomenon – can be tested with new precision.
