Nematic heavy fermions and coexisting magnetic order in CeSiI

Fuente: arXiv
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Hauptverfasser: Vijayvargia, Aayush, Erten, Onur
Format: Preprint
Veröffentlicht: 2024
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author Vijayvargia, Aayush
Erten, Onur
author_facet Vijayvargia, Aayush
Erten, Onur
contents Motivated by the recent discovery of magnetism and heavy quasiparticles in van der Waals material CeSiI, we develop an effective model that incorporates the conduction electrons residing at the silicene layer interacting with the local moments of the Ce ions. Ce sites are arranged on two layers of triangular lattices, above and below the silicene layer, and they are located at the center of the honeycomb lattice. This arrangement results in an effective extended Kondo interaction along with a predominant ferromagnetic RKKY interaction. Via mean-field theory of Abrikosov fermions, our analysis indicates that the ground state of the monolayer can exhibit a non-magnetic nematic heavy fermion phase that breaks $C_6$ rotational symmetry for small Heisenberg exchange and a magnetically ordered phase for large Heisenberg exchange. For intermediate values, a coexistence of magnetic order and a uniform heavy Fermi liquid is stabilized where they reside on separate Ce layers. We show that this phase can further be enhanced by an external electric field. Our results provide a natural mechanism for the coexistence of magnetic order and heavy fermions in CeSiI and highlight the possibility of unconventional non-magnetic heavy fermions with broken rotational symmetry.
format Preprint
id arxiv_https___arxiv_org_abs_2402_03442
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Nematic heavy fermions and coexisting magnetic order in CeSiI
Vijayvargia, Aayush
Erten, Onur
Strongly Correlated Electrons
Motivated by the recent discovery of magnetism and heavy quasiparticles in van der Waals material CeSiI, we develop an effective model that incorporates the conduction electrons residing at the silicene layer interacting with the local moments of the Ce ions. Ce sites are arranged on two layers of triangular lattices, above and below the silicene layer, and they are located at the center of the honeycomb lattice. This arrangement results in an effective extended Kondo interaction along with a predominant ferromagnetic RKKY interaction. Via mean-field theory of Abrikosov fermions, our analysis indicates that the ground state of the monolayer can exhibit a non-magnetic nematic heavy fermion phase that breaks $C_6$ rotational symmetry for small Heisenberg exchange and a magnetically ordered phase for large Heisenberg exchange. For intermediate values, a coexistence of magnetic order and a uniform heavy Fermi liquid is stabilized where they reside on separate Ce layers. We show that this phase can further be enhanced by an external electric field. Our results provide a natural mechanism for the coexistence of magnetic order and heavy fermions in CeSiI and highlight the possibility of unconventional non-magnetic heavy fermions with broken rotational symmetry.
title Nematic heavy fermions and coexisting magnetic order in CeSiI
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2402.03442