[radioactivist]

While there certainly are ideas from string theory that have filtered down to CMP, topological insulators are not one of them.

[octonion137]

That's probably true and my association of the two is probably subjective since at the time I was learning about Chern-Simons and saw it used in both contexts https://www.math.purdue.edu/~ebkaufma/RMP.pdf

[StringHool]

Chern-Simons theory is a string theory.