Discovery of an ultra-quantum spin-liquid


Varma, C. (2021). Discovery of an ultra-quantum spin-liquid. Perimeter Institute. https://pirsa.org/21050002


Varma, Chandra. Discovery of an ultra-quantum spin-liquid. Perimeter Institute, May. 03, 2021, https://pirsa.org/21050002


          @misc{ pirsa_21050002,
            doi = {10.48660/21050002},
            url = {https://pirsa.org/21050002},
            author = {Varma, Chandra},
            keywords = {Condensed Matter},
            language = {en},
            title = {Discovery of an ultra-quantum spin-liquid},
            publisher = {Perimeter Institute},
            year = {2021},
            month = {may},
            note = {PIRSA:21050002 see, \url{https://pirsa.org}}


I will talk on experiments and their interpretation done with Professor Lei Shu and her collaborators at Fudan University, Shanghai, and some tentative theory for the observations.  Thermodynamic and magnetic relaxation measurements in zero and finite magnetic field have been performed in two related almost triangular lattices of S=1/2 spins. One of these compounds is the purest of any of the potential spin-liquid compounds investigated so far. All its measured properties are extra-ordinary and characterized simply by just one parameter, the exchange energy obtained from susceptibility measurements. There are also colossal ultra-low energy singlet excitations. This may be the first characterization of the intrinsic properties of a class of spin-liquids.  An ansatz in which the excitations are calculated from a state of singlet-dimers interacting with excitations from other such singlets can be expressed in terms of Majoranas and gives properties similar to those observed.