  Twisted magnons (TMs) have great potential applications in communication and
computing owing to the orbital angular momentum (OAM) degree of freedom.
Realizing the unidirectional propagation of TMs is the key to design functional
magnonics devices. Here we theoretically study the propagation of TMs in
one-dimensional magnetic nanodisk arrays. By performing micromagnetic
simulations, we find that the one-dimensional nanodisk array exhibits a few
bands due to the collective excitations of TMs. A simple model by considering
the exchange interaction is proposed to explain the emerging multiband
structure and theoretical results agree well with micromagnetic simulations.
Interestingly, for a zigzag structure, the dispersion curves and propagation
images of TMs show obvious nonreciprocity for specific azimuthal quantum number
($l$), which originates from a geometric effect depending on the phase
difference of TMs and the relative angle between two adjacent nanodisks.
Utilizing this feature, one can conveniently realize the unidirectional
propagation of TMs with arbitrary nonzero $l$. Our work provides important
theoretical references for controlling the propagation of TMs.
