PIRSA:13030113

S=1 spin liquid with fermionic excitations

Serbyn, M. (2013). S=1 spin liquid with fermionic excitations. Perimeter Institute. https://pirsa.org/13030113

Serbyn, Maksym. S=1 spin liquid with fermionic excitations. Perimeter Institute, Mar. 28, 2013, https://pirsa.org/13030113 

          @misc{ pirsa_PIRSA:13030113,
            doi = {10.48660/13030113},
            url = {https://pirsa.org/13030113},
            author = {Serbyn, Maksym},
            keywords = {Condensed Matter},
            language = {en},
            title = {S=1 spin liquid with fermionic excitations},
            publisher = {Perimeter Institute},
            year = {2013},
            month = {mar},
            note = {PIRSA:13030113 see, \url{https://pirsa.org}}
          }

Maksym Serbyn

Massachusetts Institute of Technology (MIT)

Talk number
PIRSA:13030113
Collection
Talk Type
Subject
Abstract
In the first part of my talk I describe a search for possible quantum spin liquid ground states for spin S=1 Heisenberg models on the triangular lattice which was motivated by recent experiments on Ba3NiSb2O9.  We use representation of spin-1 via three flavors of fermionic spinon operators. The ground state where one gapless flavor of spinons with a Fermi surface coexists with d+id topological pairing of the two other flavors can explain available experimental data. Despite the existence of a Fermi surface, this spin liquid state has fully gapped bulk spin excitations. This results in a linear in-temperature specific heat and constant in-plane spin susceptibility, with an unusually high Wilson ratio. Using variational Monte Carlo technique, we show that proposed spin liquid ground state is realized in an SU(3)-invariant model with sufficiently strong ring-exchange terms.   In the second part, I consider the physics of the magnetic s=1/2 impurity embedded in a S=1 spin liquid, where all three flavors of spinons have a Fermi surface. The interplay between non-Fermi-liquid behavior induced by a U(1) gauge field coupled to fermions, and a non-Fermi-liquid fixed point in the overscreened Kondo problem is studied using double expansion. The gauge field changes the physical properties of the system at the overscreened Kondo fixed point. Thus, spin-half impurity in such spin liquid can be used to probe the presence of fermionic spinons coupled to the gauge field.   References: arXiv:1108.3070, arXiv:1208.3231 and arXiv:1212.5179