Information localization in defective spin-chain*

We study Out of time order Correlators (OTOCs) of ZY 1D spin compass model[1] which is also widely known to be the 1D analogue of 2D Kitaev spin liquid model(KSL). Among the many platforms for realizing 2D KSL on trivalent graphs like hexagon or square-octagon, our recent work[2] has shown that Cyclooctatraene(COT) based polymers form a natural candidate to realizing square-octagon lattices both in 1D & 2D with interesting topological & flat-band properties. In our current work, we consider Bond-twist/flip disorders on the 1D spin compass model wherein the vicinity of the defective site, the bonds are repeated while they preserve the alternating nature of bond structure of ZZ and YY bonds before and after the defect site. Given this defective spin chain model, We observe that the XX-OTOC: both real & imaginary[3] parts, propogate only between the start of the chain upto the defective site under open boundary conditions. The absence of OTOC signal and information scrambling beyond the defect suggests the phenomena of localization of information (LOI) in the OTOC space thus enabling us to propose OTOC as a probe to detect the aforementioned defects. Additionally, the relation between LOI & Many-Body Localized(MBL) state in this model has been explored.