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Mario A. Castro

Publications and source records attributed to Mario A. Castro.

3 recordsLinked to original sources

Magnetic topological textures in nonorientable surfaces

Topological magnetic textures confined to two-dimensional (2D) non-orientable manifolds exhibit behaviors absent in planar systems. We investigate bimerons on M\"obius surfaces and show that the lack of global orientation alters conservation laws, yielding geometry-dependent topology and dynamics. Micromagnetic simulations reveal that the helical twist and non-orientable geometry reshape the effective topological charge and stabilize chiral configurations imposed by the surface. Under spin-polarized currents, bimerons display unconventional transport: the transverse response is locally reversed or globally suppressed due to charge inversion along the manifold. Moreover, we establish an Aharonov-Bohm effect associated with the magnonic modes of the texture; in particular, the translational Goldstone mode implies that a bimeron on a M\"obius strip should exhibit path-dependent quantum interference. These results identify a geometry-driven regime of magnetization dynamics and provide a route to curvature-engineered spintronic functionalities.

cond-mat.mes-hall

Antiferron Modes in Ferroelectric Materials

We introduce the concept of antiferron modes in ferroelectric materials as dynamically stabilized collective excitations over inverted polarization states that decrease the system energy. While ferrons represent quantized oscillations around the stable polarization minimum, antiferrons require dynamic stabilization via high-frequency driving. Using a generalized Landau-Ginzburg-Devonshire framework, we derive the effective curvature corrections from external driving, demonstrate the conditions for stabilizing metastable wells, and present the quantized Hamiltonian. Antiferrons could be a promising candidate for developing electrical sensing devices, offering tunable, dynamically controllable excitations with high sensitivity to external electric fields.

cond-mat.mtrl-sci

Magnonics along the wall in Bimeron Chain Domain Walls

We demonstrate that domain walls built from bimeron chains (bc-DW) in two-dimensional systems constitute a spontaneously assembled medium that holds magnonic excitations along its direction. We prove that such magnons are topological, leading to protected edge states. We also verify the stability of the domain walls and its edge modes' resilience against disorder. Analytical calculations and micromagnetic simulations support our findings. The robustness of these edge modes holds promise for potential applications in the design of nanoscale magnonic devices for information storage and transport.

cond-mat.mes-hall