Topological Solitons in Magnetic Systems

After preliminaries about electron properties, and definitions in magnetism, one treats the magnetism of mononuclear complexes, in particular spin cross-over, showing the role of cooperativity and the sensitivity to external perturbations. Orbital interactions and exchange interaction are explained in binuclear model systems, using orbital overlap and orthogonality concepts to explain antiferromagnetic or ferromagnetic coupling. The phenomenologically useful Spin Hamiltonian is defined. The concepts are then applied to extended molecular magnetic systems, leading to molecular magnetic materials of various dimensionalities exhibiting bulk ferro- or ferrimagnetism. An illustration is provided by Prussian Blue analogues. Magnetic anisotropy is introduced. It is shown that in some cases, a slow relaxation of magnetization arises and gives rise to appealing single-ion magnets, single-molecule magnets or single-chain magnets, a route to store information at the molecular level.

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Description and symmetry of aperiodic crystals

10.1093/oso/9780198824442.003.0002 ◽

2018 ◽

Author(s):

Ted Janssen ◽

Gervais Chapuis ◽

Marc de Boissieu

Keyword(s):

Time Reversal ◽

Mathematical Concept ◽

New Materials ◽

Magnetic Systems ◽

Atomic Structures ◽

Modulated Phases ◽

Quasiperiodic Functions ◽

Aperiodic Crystals ◽

Superspace Description

This chapter first introduces the mathematical concept of aperiodic and quasiperiodic functions, which will form the theoretical basis of the superspace description of the new recently discovered forms of matter. They are divided in three groups, namely modulated phases, composites, and quasicrystals. It is shown how the atomic structures and their symmetry can be characterized and described by the new concept. The classification of superspace groups is introduced along with some examples. For quasicrystals, the notion of approximants is also introduced for a better understanding of their structures. Finally, alternatives for the descriptions of the new materials are presented along with scaling symmetries. Magnetic systems and time-reversal symmetry are also introduced.

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Particle-antiparticle duality and fractionalization of topological chiral solitons

Scientific Reports ◽

10.1038/s41598-020-80085-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Chang-geun Oh ◽

Sang-Hoon Han ◽

Seung-Gyo Jeong ◽

Tae-Hwan Kim ◽

Sangmo Cheon

Keyword(s):

Chiral Symmetry ◽

Time Reversal ◽

Chiral Symmetry Breaking ◽

Chain Model ◽

Fractional Charge ◽

Topological Solitons ◽

Practical Applications ◽

Topological System ◽

Ssh Model ◽

Chiral Solitons

AbstractAlthough a prototypical Su–Schrieffer–Heeger (SSH) soliton exhibits various important topological concepts including particle-antiparticle (PA) symmetry and fractional fermion charges, there have been only few advances in exploring such properties of topological solitons beyond the SSH model. Here, by considering a chirally extended double-Peierls-chain model, we demonstrate novel PA duality and fractional charge e/2 of topological chiral solitons even under the chiral symmetry breaking. This provides a counterexample to the belief that chiral symmetry is necessary for such PA relation and fractionalization of topological solitons in a time-reversal invariant topological system. Furthermore, we discover that topological chiral solitons are re-fractionalized into two subsolitons which also satisfy the PA duality. As a result, such dualities and fractionalizations support the topological $$\mathbb {Z}_4$$ Z 4 algebraic structures. Our findings will inspire researches seeking feasible and promising topological systems, which may lead to new practical applications such as solitronics.

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From Center-Vortex Ensembles to the Confining Flux Tube

Universe ◽

10.3390/universe7080253 ◽

2021 ◽

Vol 7 (8) ◽

pp. 253

Author(s):

David R. Junior ◽

Luis E. Oxman ◽

Gustavo M. Simões

Keyword(s):

Degrees Of Freedom ◽

String Tension ◽

Effective Field ◽

Scaling Properties ◽

Flux Tubes ◽

Topological Solitons ◽

Yang Mills ◽

Center Vortex ◽

Asymptotic Scaling ◽

The Continuum

In this review, we discuss the present status of the description of confining flux tubes in SU(N) pure Yang–Mills theory in terms of ensembles of percolating center vortices. This is based on three main pillars: modeling in the continuum the ensemble components detected in the lattice, the derivation of effective field representations, and contrasting the associated properties with Monte Carlo lattice results. The integration of the present knowledge about these points is essential to get closer to a unified physical picture for confinement. Here, we shall emphasize the last advances, which point to the importance of including the non-oriented center-vortex component and non-Abelian degrees of freedom when modeling the center-vortex ensemble measure. These inputs are responsible for the emergence of topological solitons and the possibility of accommodating the asymptotic scaling properties of the confining string tension.

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Elastic behavior of magnetic systems with a narrow twofold-degenerate band

Physical Review B ◽

10.1103/physrevb.36.3868 ◽

1987 ◽

Vol 36 (7) ◽

pp. 3868-3873 ◽

Cited By ~ 11

Author(s):

D. K. Ray ◽

S. K. Ghatak

Keyword(s):

Elastic Behavior ◽

Magnetic Systems

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