Abstract

Pyrochlore oxides are a very rich family in magnetism where each member brings its own personality. If some materials and models exhibit exotic phase transitions away from the Ginzburg-Landau paradigm, other are able to avoid ordering such as spin ice (Dy2Ti2O7) or potential spin liquids (Tb2Ti2O7). Yb2Ti2O7 for example has generated considerable excitement lately as a potential example of a “quantum spin-ice”.

Here we show how it is possible to construct a unified picture of ground state and excitations in a wide range of such materials. Our starting point is a simple effective field theory which explains both the dimensional reduction seen in Yb2Ti2O7, and the ground-state selection in Er2Ti2O7. It also provides a general recipe to find emergent electromagnetism in such models. These results are combined with spin wave calculations and extensive classical Monte Carlo simulations to provide a comprehensive picture of the interplay between order and finite temperature excitations in pyrochlore oxides with highly-anisotropic exchange interactions.