Suppressing backscattering of helical edge modes with a spin bath

• We address the question of stability of protected helical edge states at the boundary of two-dimensional topological insulators upon interactions with the external bath. We study how backscattering amplitude changes when different interaction channels between the system and the environment are present. Drawing an analogy with the concept of pointer states in theory of open quantum systems, we demonstrate that in a certain regime the interplay between the Coulomb and the spin-spin interactions can make the backscattering process strictly irrelevant, and the helical modes become robust states with a well-defined momentum. This opens a possibility to use the external spin bath as a stabilizer that alleviates destructive effects and restores the helicity protection.

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NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

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