Chirality waves in two-dimensional magnets

We theoretically show that moderate interaction between electrons confined to move in a plane and localized magnetic moments leads to formation of a noncoplanar magnetic state. The state is similar to the Skyrmion crystal recently observed in cubic systems with the Dzyaloshinskii-Moriya interaction; however, it does not require spin-orbit interaction. The noncoplanar magnetism is accompanied by the ground-state electrical and spin currents, generated via the real-space Berry phase mechanism. We examine the stability of the state with respect to lattice discreteness effects and the magnitude of magnetic exchange interaction. The state can be realized in a number of transition metal and magnetic semiconductor systems.     

Ferromagnetic resonance for one-dimensional magnets with solitons

The ferromagnetic resonance phenomenon is considered in one-dimensional magnets in which the envelope solitions can appear. The existence of solitons influences the ferromagnetic resonance spectrum and therefore the resonance technique seems to be a possible tool in order to identify the existence of solitons and their properties.     

Stabilized two-dimensional vector solitons

In this Letter, we introduce the concept of stabilized vector solitons as nonlinear waves constructed by the addition of mutually incoherent fractions of Townes solitons that are stabilized under the effect of a periodic modulation of the nonlinearity. We analyze the stability of these new kinds of structures and describe their behavior and formation in Manakov-like interactions. Potential applications of our results in Bose-Einstein condensation and nonlinear optics are also discussed.     

Magnetic relaxation in two-dimensional molecular magnets

Magnetic properties of planar molecular magnets have been investigated by Mössbauer spectroscopy. A significant increase in the linewidth of the magnetic hyperfine structure with an increase in temperature is observed. A fluctuation model of magnetism for magnets lacking long-range magnetic order is proposed. This model describes the magnetic field distributions in these magnets in a wide temperature range with the use of a fixed set of coupling constants.     

Observation of two-dimensional surface solitons

We report the first experimental observation of two-dimensional surface solitons at the boundaries (edges or corners) of a finite optically induced photonic lattice. Both in-phase and gap nonlinear surface self-trapped states were observed under single-site excitation conditions. Our experimental results are in good agreement with theoretical predictions.     

Microwave solitons in molecular magnets via electromagnetically induced transparency

Using the Schrödinger-Maxwell equations, we investigate the formation of microwave solitons in a crystal of molecular magnets. This system is subjected to one dc magnetic field and two (probe and coupling) ac resonant magnetic fields. The results show that the probe magnetic field can freely propagate in a crystal of molecular magnets due to quantum interference. Furthermore, within certain parameter range, both bright and dark microwave solitons can occur in such a highly resonant medium. We also obtain the analytical expressions for the phase shift and absorption coefficient of the probe magnetic field.     

Observation of two-dimensional multimode solitons

We present the first experimental observation of (2+1) -dimensional multimode (composite) solitons. A single-hump component and a double-hump (dipole-type) component are jointly self-trapped as a composite soliton in a biased photorefractive crystal.     

Reduced-symmetry two-dimensional solitons in photonic lattices

We demonstrate theoretically and experimentally a novel type of localized beam supported by the combined effects of total internal and Bragg reflection in nonlinear two-dimensional square periodic structures. Such localized states exhibit strong anisotropy in their mobility properties, being highly mobile in one direction and trapped in the other, making them promising candidates for optical routing in nonlinear lattices.     

Dynamics of topological solitons in two-dimensional ferromagnets

Dynamical topological solitons are studied in classical two-dimensional Heisenberg easy-axis ferromagnets. The properties of such solitons are treated both analytically in the continuum limit and numerically by spin dynamics simulations of the discrete system. Excitation of internal mode causes orbital motion. This is confirmed by simulations.     

Partition function for two-dimensional solitons

The partition function for two-dimensional scalar field theories which possess soliton states, is constructed in the semi-classical approximation. Divergences are handled by using zeta-function methods. The result is naturally interpretated after the appropriate mass renormalisations, as being that due to a massive particle confined in a box.