Sitemap
A list of all the posts and pages found on the site. For you robots out there, there is an XML version available for digesting as well.
Pages
Posts
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Published:
This is a sample blog post. Lorem ipsum I can’t remember the rest of lorem ipsum and don’t have an internet connection right now. Testing testing testing this blog post. Blog posts are cool.
notes
One-Dimensional Ising Model: Phase Transition, Symmetry Breaking, and the Critical Exponent of Heat Capacity at Constant Volume
Published:
Created a note titled “One-Dimensional Ising Model: Phase Transition, Symmetry Breaking, and the Critical Exponent of Heat Capacity at Constant Volume”. Available only in the Chinese version “一维伊辛(Ising)模型: 相变，对称性破缺与定积热容的临界指数”.
From Classical Heisenberg Model to Spiral Magnetism
Published:
Created a note titled “From Classical Heisenberg Model to Spiral Magnetism”, which guides readers through using the classical Heisenberg model to determine the conditions under which spiral magnetic configuration emerges. Available in both the Chinese version “从古典海森堡模型到螺旋磁性” and the Japanese version “古典 Heisenberg 模型から螺旋磁性へ”. An English version is not yet available.
portfolio
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Short description of portfolio item number 1
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Short description of portfolio item number 2
publications
Square skyrmion lattice in multiorbital $f$-electron systems
Published in Physical Review B, 2025
Abstract: We report the emergence of a square-shaped skyrmion lattice in multiorbital $f$-electron systems with easy-axis magnetic anisotropy on a centrosymmetric square lattice. By performing mean-field calculations for an effective localized model consisting of two Kramers doublets, we construct the low-temperature phase diagram in a static external magnetic field. Consequently, we find that a square-shaped skyrmion lattice with the skyrmion number of one appears in the intermediate-field region when the crystal field splitting between the two doublets is small. Furthermore, we identify another double-$Q$ state with a nonzero net scalar chirality at zero- and low-field regions, which is attributed to the help of the multiorbital degree of freedom. Our results offer another route to search for skyrmion-hosting materials in centrosymmetric $f$-electron tetragonal systems with multiorbital degrees of freedom, e.g., Ce-based compounds. This contrasts with conventional other $f$-electron systems hosting skyrmion lattices, such as Gd- and Eu-based compounds without orbital angular momentum.
Recommended citation: Y. Zha and S. Hayami, Square skyrmion lattice in multiorbital $f$-electron systems, Phys. Rev. B \bf{111}, 165155 (2025).
Effects of crystal field and momentum-based frustrated exchange interactions on multiorbital square skyrmion lattice
Published in arXiv, 2025
Abstract: Motivated by recent theoretical predictions of a square-shaped skyrmion lattice (S-SkL) in centrosymmetric tetragonal Ce-based magnets [Yan Zha and Satoru Hayami, Phys. Rev. B 111, 165155 (2025)}], we perform a comprehensive theoretical investigation on the role of multiorbital effects, magnetic anisotropy, and momentum-based frustrated exchange interactions in stabilizing such topologically nontrivial magnetic textures. By employing self-consistent mean-field calculations over a broad range of model parameters, we demonstrate that the cooperative interplay among multiorbital effects, frustrated exchange interactions at higher-harmonic wave vectors, and crystal-field anisotropy is crucial for the stabilization of the S-SkL. Furthermore, the competition between the easy-plane intraorbital coupling and the easy-axis interorbital coupling leads to a significant enhancement of the S-SkL stability region. We also identify a plethora of multi-Q states, including magnetic bubble lattice and double-Q phases with a local/global scalar chirality. Our findings elucidate the microscopic mechanism responsible for the emergence of S-SkLs in Ce-based magnets and provide a route toward realizing skyrmion lattices in a broader class of f-electron materials beyond conventional Gd- and Eu-based systems lacking orbital angular momentum.
Recommended citation: Y. S. Zha and S. Hayami, Effects of crystal field and momentum-based frustrated exchange interactions on multiorbital square skyrmion lattice (2025), arXiv:2511.05896 [cond-mat.str-el].
talks
Workshop on theory of cross correlations, multipoles, and computational material design
Published:
Gave a poster presentation titled “Mean-field analysis of a square skyrmion lattice in multi-orbital $f$-electron systems” at “Workshop on theory of cross correlations, multipoles, and computational material design”url. @Gotemba Tokinosumika, Gotemba, Shizuoka, Japan (UTC+09:00)
The Physical Society of Japan 2025 Spring Meeting Online Virtual Meeting
Published:
Gave an oral presentation titled “Mean-field analysis of a square skyrmion lattice in multi-orbital $f$-electron systems” (18pH2-8) at the “The Physical Society of Japan 2025 Spring Meeting Online Virtual Meeting”url. @Online (UTC+09:00)
The Physical Society of Japan 2025 Annual Meeting
Published:
Gave an oral presentation titled “Effects of Crystal Field and Momentum-Based Frustrated Interaction on Multiorbital Square Skyrmion Lattice” (19aSK314-7) at the “The Physical Society of Japan 2025 Annual Meeting”url. @Hiroshima University, Higashihiroshima, Hiroshima, Japan (UTC+09:00)
teaching
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Undergraduate course, University 1, Department, 2014
This is a description of a teaching experience. You can use markdown like any other post.