Today, information in logic applications is mostly carried by the electric current of electrons and holes in semiconductors. There is however a rapidly growing interest in the transmission of information encoded by electron and atomic spins which, in principle, can be realized by the propagation of spin-waves or magnetization waves through low-dimensional ferromagnets.
Genuine spin waves originate from deviations of individual, single spins with respect to the perfectly ordered ground state of a ferromagnet in which all spins are aligned parallel to each other. The waves that are propagating such deviations through the lattice of the ferromagnet are called spin waves and, as such, they can be excited only at very low temperatures. However, at room temperature one may excite similar waves, corresponding to the spatial variation of the macroscopic magnetization vector that locally deviates from the spontaneous magnetization.
Although the basic quantum theory of ferromagnetism has been established already in the previous century, various fundamental problems are left unsolved or remain to be highly controversial, especially those concerning low-dimensional magnets. Rather than relying on semi-classical theories and simulation programs, the research of this PhD will focus on the fundamental physics of both the equilibrium properties and the spin dynamics of one- or two-dimensional ferromagnets, all to be studied in the framework of quantumstatistical and condensed matter physics