Quantum spin ice: a search for gapless quantum spin liquids in pyrochlore magnets.
The spin ice materials, including Ho2Ti2O7 and Dy2Ti2O7, are rare-earth pyrochlore magnets which, at low temperatures, enter a constrained paramagnetic state with an emergent gauge freedom. Spin ices provide one of very few experimentally realized examples of fractionalization because their elementary excitations can be regarded as magnetic monopoles and, over some temperature range, spin ice materials are best described as liquids of these emergent charges. In the presence of quantum fluctuations, one can obtain, in principle, a quantum spin liquid descended from the classical spin ice state characterized by emergent photon-like excitations. Whereas in classical spin ices the excitations are akin to electrostatic charges with a mutual Coulomb interaction, in the quantum spin liquid these charges interact through a dynamic and emergent electromagnetic field. In this review, we describe the latest developments in the study of such a quantum spin ice, focusing on the spin liquid phenomenology and the kinds of materials where such a phase might be found.
Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada. Perimeter Institute for Theoretical Physics, 31 Caroline North, Waterloo, Ontario, N2L 2Y5, Canada. Canadian Institute for Advanced Research, Toronto, Ontario, M5G 1Z8, Canada.
M J P
MJ
Gingras
P A
PA
McClarty
D059346:Magnets; D008956:Models, Chemical; D009556:Niobium / Q000737:chemistry*; D011789:Quantum Theory; D012996:Solutions / Q000737:chemistry*; D013113:Spin Labels
D012996:Solutions; D013113:Spin Labels; D009556:Niobium; C016709:pyrochlore