Quasicrystalline chiral soliton lattices in a Fibonacci helimagnet

Abstract

We investigate the ground state magnetic configurations of a Fibonacci chain of classical spins with nearest-neighbor ferromagnetic and monoaxial Dzyaloshinskii-Moriya exchange interactions. Our analysis reveals a diverse array of magnetic textures induced by an external magnetic field perpendicular to the Dzyaloshinskii-Moriya vector. These textures exhibit a spectrum ranging from a quasifully polarized noncollinear state under high magnetic fields, capable of maintaining metastable chiral soliton topological defects, to a variety of quasicrystalline chiral soliton lattices below a critical field 𝐻𝑐. For a range of magnetic fields below 𝐻𝑐, the ground state spin textures result from the interplay between an effective quasiperiodic potential influencing the solitons and their repulsive interactions. At lower magnetic fields, the system experiences a commensurate-incommensurate transition, signified by the appearance of discommensurations in the quasicrystalline soliton lattice. In the absence of an external magnetic field, the ground state assumes a helical configuration with a quasiperiodic pitch angle.