This rendering illustrates the excitation of a spin liquid on a honeycomb lattice using neutrons. As with many other liquids, it is difficult to see a spin liquid unless it is “splashed,” in this case by neutrons depicted as moving balls. The misaligned and vibrating spin pair in the middle signifies the ephemeral Majorana fermion constantly in motion. The ripples formed when the neutrons hit the spin liquid represent the excitations that are a signature of the Majorana fermions. The atomic structure on the left signifies the honeycomb alpha-ruthenium trichloride, in which each ruthenium atom has a spin and is surrounded by a cage of chlorine atoms.
Researchers from the U.S. Department of Energy’s Oak Ridge National Laboratory and UT’s Department of Materials Science and Engineering and Department of Physics and Astronomy used neutrons to uncover novel behavior in materials that holds promise for quantum computing.
The findings, published in Nature Materials, provide evidence for long-sought phenomena in a two-dimensional magnet.
Related—The news generated interest around the world. Here are some of those stories from major outlets:
CBS News: New bizarre state of matter seems to split fundamental particles
Yahoo News: Physicists just discovered a new state of matter called ‘quantum spin liquid’
Popular Science: In a new state of matter, electrons can break into pieces
Wired: Scientists just discovered a new state of matter
Arnab Banerjee, a post-doctoral researcher at ORNL, explained that one way to observe spin liquid physics is to “splash” or excite the liquid using neutron scattering.
UT Jerry and Kay Henry Endowed Professor David Mandrus and research professor Jiaqiang Yan—both of the Department of Materials Science and Engineering and joint faculty with ORNL—along with materials science student Ling Li and physics student Yuen Yiu joined Banerjee and colleagues from ORNL, the Max Planck Institute in Dresden, Germany and Cambridge University in the United Kingdom on the team.
They used the “splash” technique to investigate a two-dimensional graphene-like material, alpha-ruthenium trichloride. Neutrons shining onto and scattering from the material can deposit small amounts of energy that create magnetic excitations.
In 2006, the physicist Alexei Kitaev developed a theoretical model of microscopic magnets [spins] that interact in a fashion that leads to a disordered state called a quantum spin liquid. This “Kitaev quantum spin liquid” supports magnetic excitations equivalent to Majorana fermions—particles that are unusual in that they are their own antiparticles.
The presence of Majorana fermions is of great interest because of their potential use as the basis for a qubit, the essential building block of quantum computers.
The full release can be seen here