Title: Spin- and Flux-gap Renormalization in the Random Kitaev Spin Ladder.
Speaker: Wen-Han Kao (University of Minnesota)
Start Date/Time: 2022-06-08 / 10:30 (Taipei time)
End Date/Time: 2022-06-08 / 12:00
Venue: Online Zoom [Registration] is required
Host : Prof. Yi-Ping Huang (Department of Physics, NTHU)

Abstract : We study the Kitaev spin ladder with random couplings by using the real-space strong-disorder renormalization group (SDRG) technique. This model is the minimum model in Kitaev systems that has conserved plaquette fluxes, and its quasi-one-dimensional geometry makes it possible to study the strong-disorder fixed points for both spin and flux excitations. In the Ising limit, the behavior of the spin gap is consistent with the familiar random transverse-field Ising chain with accessible analytic solutions, but the flux gap is dominated by the additional y-couplings. In the XX limit, while the x- and y-couplings are renormalized simultaneously, the z-couplings are not renormalized drastically and lead to non-universal disorder criticality at low-energy scales. Our work points out a new complexity in understanding the strong-disorder effect in frustrated spin systems with local conserved quantities.

Zoom link: https://us02web.zoom.us/j/82485760144?pwd=WjhaVHplU2hvd0JJV2gvYU82MVFWdz09