Topological piezomagnetic effect in two-dimensional Dirac quadrupole altermagnets
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| Format: | Preprint |
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2026
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| _version_ | 1866913051690663936 |
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| author | Radhakrishnan, H. Bell, B. Ortix, C. Venderbos, J. W. F. |
| author_facet | Radhakrishnan, H. Bell, B. Ortix, C. Venderbos, J. W. F. |
| contents | Altermagnets provide a natural platform for studying and exploiting piezomagnetism. In this paper, we introduce a class of insulating altermagnets in two dimensions (2D) referred to as Dirac quadrupole altermagnets, and show based on microscopic minimal models that the orbital piezomagnetic polarizability of such altermagnets has a topological contribution described by topological response theory. The essential low-energy electronic structure of Dirac quadrupole altermagnets can be understood from a gapless parent phase (i.e., the Dirac quadrupole semimetal), which has important implications for their response to external fields. Focusing on the strain-induced response, here we demonstrate that the topological piezomagnetic effect is a consequence of the way in which strain affects the Dirac points forming a quadrupole. We consider two microscopic models: a spinless two-band model describing a band inversion of $s$ and $d$ states, and a Lieb lattice model with collinear Néel order. The latter is a prototypical minimal model for altermagnetism in 2D and is realized in a number of recently proposed material compounds, which are discussed. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2602_05894 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Topological piezomagnetic effect in two-dimensional Dirac quadrupole altermagnets Radhakrishnan, H. Bell, B. Ortix, C. Venderbos, J. W. F. Strongly Correlated Electrons Materials Science Altermagnets provide a natural platform for studying and exploiting piezomagnetism. In this paper, we introduce a class of insulating altermagnets in two dimensions (2D) referred to as Dirac quadrupole altermagnets, and show based on microscopic minimal models that the orbital piezomagnetic polarizability of such altermagnets has a topological contribution described by topological response theory. The essential low-energy electronic structure of Dirac quadrupole altermagnets can be understood from a gapless parent phase (i.e., the Dirac quadrupole semimetal), which has important implications for their response to external fields. Focusing on the strain-induced response, here we demonstrate that the topological piezomagnetic effect is a consequence of the way in which strain affects the Dirac points forming a quadrupole. We consider two microscopic models: a spinless two-band model describing a band inversion of $s$ and $d$ states, and a Lieb lattice model with collinear Néel order. The latter is a prototypical minimal model for altermagnetism in 2D and is realized in a number of recently proposed material compounds, which are discussed. |
| title | Topological piezomagnetic effect in two-dimensional Dirac quadrupole altermagnets |
| topic | Strongly Correlated Electrons Materials Science |
| url | https://arxiv.org/abs/2602.05894 |