Magnetic charge and ordering in kagome spin ice

• Published in: Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences Vol. 370; no. 1981; pp. 5718 - 5737
• Main Authors: Chern, Gia-Wei, Tchernyshyov, Oleg
• Format: Journal Article
• Language: English
• Published: England The Royal Society Publishing 28.12.2012; The Royal Society
• Subjects: Critical temperature; Dimers; Ground state; Ice; Low temperature; Magnetic Charge; Magnetic monopoles; Magnetic Ordering; Magnets; Mathematical lattices; Specific heat; Spin Ice; Universality
• ISSN: 1364-503X; 1471-2962
• DOI: 10.1098/rsta.2011.0388

We present a numerical study of magnetic ordering in spin ice on kagome, a two-dimensional lattice of corner-sharing triangles. The magnet has six ground states and the ordering occurs in two stages, as one might expect for a six-state clock model. In spin ice with short-range interactions up to second neighbours, there is an intermediate critical phase separated from the paramagnetic and ordered phases by Kosterlitz-Thouless (KT) transitions. In dipolar spin ice, the intermediate phase has long-range order of staggered magnetic charges. The high- and low-temperature phase transitions are of the Ising and 3-state Potts universality classes, respectively. Freeze-out of defects in the charge order produce a very large spin correlation length in the intermediate phase. As a result of that, the lower-temperature transition appears to be of the KT type.