Image courtesy of Young Lee, MIT
Inelastic neutron scattering of high-quality single-crystal samples of the mineral ZnCu3(OD)6Cl2 revealed that the scattered neutrons have a broad spread of energies (light green diffuse regions in figure), a hallmark signature predicted by theory.
Experiments, for the first time, confirm theoretical predictions of a new type of magnetism, the quantum spin liquid (QSL) state, wherein the electron spins associated with the material's magnetism continue to have motion even at absolute zero temperature (-273°C or nearly -460°F).
The current discovery and future research on this new type of frustrated magnetic materials can lead to a deeper understanding of high-temperature superconductivity and to potential applications in quantum information for future computers.
Confirming earlier theoretical predictions, a hallmark signature of a new kind of magnetic behavior, called the "quantum spin liquid" (QSL), has been observed. Unlike normal magnets wherein the electron spins freeze into an ordered state below a threshold temperature, in a QSL the electron spins associated with the material's magnetism continue to have motion even at absolute zero temperature. Through characterization by inelastic neutron scattering on large high-quality, single-crystal samples of the mineral ZnCu3(OD)6Cl2, the team, led by the Massachusetts Institute of Technology, discovered that the scattered neutrons have a broad spread of energies, a fundamental signature predicted by theory for a QSL. In normal magnets the scattered neutrons will have similar energy and produce “spots” rather than the diffuse intensity. The QSL can be thought of as the third fundamental state of magnetism; the first two states being the ferromagnet (all spins aligned parallel, as in a compass needle) and antiferromagnet (adjacent spins point in opposite directions, as in hard drive read heads). Research on QSL systems can lead to a deeper understanding of high temperature superconductivity and to potential applications in quantum information for future computers.
Massachusetts Institute of Technology
Basic Research: DOE Office of Science, Basic Energy Sciences program; Neutron scattering was performed at the National Institute of Standards and Technology (NIST).
Tian-Heng Han, Joel S. Helton, Shaoyan Chu, Daniel G. Nocera, Jose A. Rodriguez-Rivera, Collin Broholm, Young S. Lee, “Fractionalized excitations in the spin-liquid state of a kagome-lattice antiferromagnet” Nature 492, 406-410, 2012.
Collaborations, Non-DOE Interagency Collaboration