Twofold topological phase transitions induced by third-nearest-neighbor interactions in 1D chains

Abstract

Strong long-range interactions up to third nearest neighbors may induce a topological phase transition in one-dimensional chains. Unlike the Su-Schrieffer-Heeger model, this transition from trivial to topological phase occurs with the emergence of a pseudospin valley structure and a twofold nontrivial topological phase. Within a tight-binding approach, these topological phases are analyzed in detail and it is shown that the low-energy excitations follow a modified Dirac equation. An experimental realization in a one-dimensional elastic chain, where it is feasible to tune directly the third-nearest-neighbor interaction strength, is proposed.Comment: 6 pages, 3 figure