By Cameron Chai
Using a neutron scattering technique, researchers from the Institut Laue-Langevin (ILL) have performed a study on two-dimensional fermion liquids and identified a new type of density wave with very short wave-length.
Since high-temperature superconductivity may result from this kind of density waves, the study will create interest in researchers focusing on electronic systems.
Fermion liquids are made of a group of fermion particles that include neutrons, protons, electrons and quarks. The fermion liquid is one of the two kinds of quantum liquids used in ‘many-body physics’ to demonstrate the complex interaction between atoms. The liquids are commonly found in neutron stars, semiconductors, metals and atomic nuclei. The fundamental physics of other forms of quantum liquid that include photons and gluons is well understood, while fermion liquids continue to be a mystery.
Hence, a research team including Johannes Kepler University in Austria, Oak Ridge National Laboratory and SUNY University at Buffalo in the US, Aalto University in Finland and the CNRS (Centre National de la Recherche Scientifique) in France performed the first study on fermion liquids. The researchers used a layer of helium-3 as a fermi liquid. They were able to detect very short wave-length, high-frequency density waves in the helium, which remained for a longer period of time than those observed in bulk liquids during earlier experiments carried out at the ILL. These shorter wave-length density waves are termed as zero-sound mode oscillations. After completing the study on helium properties, the team will focus on electron liquids.