Recent developments in the physics of spin ice and related quantum cousin

          @misc{ pirsa_PIRSA:10050073,
            doi = {10.48660/10050073},
            url = {https://pirsa.org/10050073},
            author = {Gingras, Michel},
            keywords = {},
            language = {en},
            title = {Recent developments in the physics of spin ice and related quantum cousin},
            publisher = {Perimeter Institute},
            year = {2010},
            month = {may},
            note = {PIRSA:10050073 see, \url{https://pirsa.org}}
          }
          

Abstract

In the Ho2Ti2O7 and Dy2Ti2O7 magnetic pyrochlore oxides, the Ho and Dy Ising magnetic moments interact via geometrically frustrated effective ferromagnetic coupling. These systems possess and extensive zero entropy related to the extensive entropy of ice water -- hence the name spin ice. The classical ground states of spin ice obey a constraint on each individual tetrahedron of interacting spins -- the so-called "ice rules". At large distance, the ice-rules can be described by an effective divergent-free field and, therefore, by an emergent classical gauge theory. In contrast, while it would appear at first sight to relate to the spin ices, the Tb2Ti2O7 material displays properties that much differ from spin ices and the behaviour of that system has largely remained unexplained for over ten years. In this talk, I will review the key features of the (Ho,Dy)2Ti2O7 spin ice materials, discuss the recent experimental results that support the emergent gauge theory description of spin ices and discuss how Tb2Ti2O7 is perhaps a ''quantum melted'' spin ice.