From local spin nematicity to altermagnets: Footprints of band topology

Fuente: arXiv
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Auteurs principaux: Das, Sanjib Kumar, Roy, Bitan
Format: Preprint
Publié: 2024
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author Das, Sanjib Kumar
Roy, Bitan
author_facet Das, Sanjib Kumar
Roy, Bitan
contents Altermagnets are crystallographic rotational symmetry breaking spin-ordered states, possessing a net zero magnetization despite manifesting Kramer's non-degenerate bands. Here, we show that momentum-independent local spin nematic orders in monolayer, Bernal bilayer, and rhombohedral trilayer graphene give rise to $p$-wave, $d$-wave, and $f$-wave altermagnets, respectively, thereby inheriting the topology of linear, quadratic and cubic free fermion band dispersions that are also described in terms of angular momentum $\ell=1,\; 2$, and $3$ harmonics in the reciprocal space. The same conclusions also hold inside a spin-triplet nematic superconductor, featuring Majorana altermagnets. Altogether, these findings highlight the importance of electronic band structure in identifying such exotic magnetic orders in quantum materials. We depict the effects of in-plane magnetic fields on altermagnets, and propose spin-disordered alter-valley magnets in these systems.
format Preprint
id arxiv_https___arxiv_org_abs_2403_14620
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle From local spin nematicity to altermagnets: Footprints of band topology
Das, Sanjib Kumar
Roy, Bitan
Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Superconductivity
Altermagnets are crystallographic rotational symmetry breaking spin-ordered states, possessing a net zero magnetization despite manifesting Kramer's non-degenerate bands. Here, we show that momentum-independent local spin nematic orders in monolayer, Bernal bilayer, and rhombohedral trilayer graphene give rise to $p$-wave, $d$-wave, and $f$-wave altermagnets, respectively, thereby inheriting the topology of linear, quadratic and cubic free fermion band dispersions that are also described in terms of angular momentum $\ell=1,\; 2$, and $3$ harmonics in the reciprocal space. The same conclusions also hold inside a spin-triplet nematic superconductor, featuring Majorana altermagnets. Altogether, these findings highlight the importance of electronic band structure in identifying such exotic magnetic orders in quantum materials. We depict the effects of in-plane magnetic fields on altermagnets, and propose spin-disordered alter-valley magnets in these systems.
title From local spin nematicity to altermagnets: Footprints of band topology
topic Mesoscale and Nanoscale Physics
Strongly Correlated Electrons
Superconductivity
url https://arxiv.org/abs/2403.14620