Living on the edge: multiphase competition in Yb2Ti2O7 and monopole crystal in Tb2Ti2O7

          @misc{ pirsa_PIRSA:17060039,
            doi = {10.48660/17060039},
            url = {https://pirsa.org/17060039},
            author = {Jaubert, Ludovic},
            keywords = {Condensed Matter},
            language = {en},
            title = {Living on the edge: multiphase competition in Yb2Ti2O7  and monopole crystal in Tb2Ti2O7},
            publisher = {Perimeter Institute},
            year = {2017},
            month = {jun},
            note = {PIRSA:17060039 see, \url{https://pirsa.org}}
          }
          

Abstract

Yb2Ti2O7 and Tb2Ti2O7 share the common point to sit at the edge between different phases. This multiphase competition makes the characterization of their low-temperature physics a challenge and, more generally, brings another degree of complexity to rare-earth pyrochlores. In this talk, we will take two different approaches to study these materials. For Yb2Ti2O7, we explicitly investigate the influence of thermal and quantum fluctuations in this competition, with finite-temperature order by disorder and quantum shifting of the phase boundaries. For Tb2Ti2O7, we will step away from the puzzling zero-field physics, and explain the undisputed order observed experimentally in a high [110] field. This order strongly supports the presence of magneto-electric coupling in Tb2Ti2O7, and offers a rare example of long-range order of magnetic monopoles.