Dr. Yin-Chen He (Max-Planck-Institute PKS)
"Spin liquids on kagome lattice and symmetry protected topological phase"
In my talk I will introduce the spin liquid phases that occur in kagome antiferromagnets, and discuss
their physical origin that are closely related with the newly discovered symmetry protected topological
phase (SPT). I will first present our numerical (DMRG) study on the kagome XXZ spin model that exhibits
two distinct spin liquid phases, namely the chiral spin liquid and the kagome spin liquid (the
groundstate of the nearest neighbor kagome Heisenberg model). Both phases extend from the extreme easy-axis
limit, through SU(2) symmetric point, to the pure easy-plane limit. The two phases are separated by a
continuous phase transition. Motivated by these numerical results, I will then focus on the easy-axis
kagome spin system, and reformulate it as a lattice gauge model. Such formulation enables us to achieve
a controlled theoretical description for the spin liquid phases. We then show that the chiral spin liquid
is indeed a gauged U(1) SPT phase. On the other, we also propose that the kagome spin liquid is a critical
spin liquid phase, which can be considered as a gauged deconfined critical point between a SPT and a
superfluid phase.
[1] Yin-Chen He, Yohei Fuji, and Subhro Bhattacharjee, arXiv:1512.05381 (2015).
[2] Yin-Chen He, Subhro Bhattacharjee, Frank Pollmann, and R. Moessner, PRL 115, 267209 (2015).
[3] Yin-Chen He, Subhro Bhattacharjee, R. Moessner, and Frank Pollmann, PRL 115, 116803 (2015).
[4] Yin-Chen He and Yan Chen, PRL 114, 037201 (2015).
[5] Yin-Chen He, D. N. Sheng and Yan Chen, PRL 112, 137202 (2014).