Fig. 1: Domain walls in dimer and trimer chains.
From: Tuneable topological domain wall states in engineered atomic chains
a, b Schematic of dimer (a) and trimer (b) chain with a domain wall. c Calculated energy spectra of finite dimer and trimer chains hosting a domain wall with t1 = 0.14 eV, t2 = 0.04 eV8 calculated with 300 unit cells on both sides of the domain wall. While the in-gap state in a dimer chain is pinned to mid-gap, domain wall in a trimer chain results tunable in-gap states depending on the hopping t3.
