Particle-antiparticle duality and fractionalization of topological chiral solitons

Abstract

Although a prototypical Su–Schrieffer–Heeger (SSH) soliton exhibits various important topological concepts including particle-antiparticle (PA) symmetry and fractional fermion charges, there have been only few advances in exploring such properties of topological solitons beyond the SSH model. Here, by considering a chirally extended double-Peierls-chain model, we demonstrate novel PA duality and fractional charge e/2 of topological chiral solitons even under the chiral symmetry breaking. This provides a counterexample to the belief that chiral symmetry is necessary for such PA relation and fractionalization of topological solitons in a time-reversal invariant topological system. Furthermore, we discover that topological chiral solitons are re-fractionalized into two subsolitons which also satisfy the PA duality. As a result, such dualities and fractionalizations support the topological $$\mathbb {Z}_4$$ Z 4 algebraic structures. Our findings will inspire researches seeking feasible and promising topological systems, which may lead to new practical applications such as solitronics.

Topological and trivial domain wall states in engineered atomic chains

“…Note that Fig. 2b, c now exhibit the topologically opposite chirality, which has been reported in other systems 5,6,8 .…”

“…Their system allows to experimentally tune the domain wall states using atom manipulation by the tip of a scanning tunneling microscope (STM). They have realized topological domain wall states of two prototypical one-dimensional models such as trimer 3 and coupled dimer chains [4][5][6][7][8] . However, they did not distinguish trivial domain wall states 9 from topological ones in their models.…”

“…By coupling two SSH chains, we introduce a coupled dimer chain with four ground states where topological chiral domain wall states can emerge when one of two SSH subchains has an interface between topologically distinct Zak phases [5][6][7][8] . However, the defective domain wall AA → AB (Fig.…”

Topological and trivial domain wall states in engineered atomic chains

“…Note that Fig. 2b and c now exhibit the topologically opposite chirality, which has been reported in other systems 5,6,8 . On the other hand, Fig.…”

Defect-induced solitons in double Peierls chain model

“…Recently, chiral solitons and their topological operations were discovered in double Peierls chains of indium atomic wires and were suggested as a new multi-digit information carrier [26,27,[43][44][45][46]. This work expanded the SSH model, providing a new degree of freedom-chirality.…”