Gradual Localization of Itinerant Cobalt 3d Electrons in the Pyrochlore Ferromagnetic Metal LuInCo4

Taiki Shiotani; Subaru Yoshimoto; Yoshikazu Tabata; Yusuke Nambu; Katsuki Kinjo; Kazuhiro Nawa; Taku J. Sato; Takeshi Waki; Hiroyuki Nakamura

arXiv · 2610.08266

Gradual Localization of Itinerant Cobalt 3d Electrons in the Pyrochlore Ferromagnetic Metal LuInCo4

Taiki Shiotani·Subaru Yoshimoto·Yoshikazu Tabata·Yusuke Nambu·Katsuki Kinjo·Kazuhiro Nawa·Taku J. Sato·Takeshi Waki·Hiroyuki Nakamura

View original source ↗Read source document ↗Export metadata ↓

Abstract

We investigated the microscopic magnetic state of the itinerant-electron ferromagnet LuInCo4 with a cobalt pyrochlore lattice by means of powder and single-crystal neutron diffraction measurements. The powder neutron diffraction profiles at zero field are well described by a simple q = 0 collinear ferromagnetic structure with an ordered Co moment of 0.9 uB. Single-crystal neutron diffraction experiments further suggest the absence of both antiferromagnetic order and long-period helical magnetic modulation. In addition, diffuse magnetic scattering was observed around q = 0, with its intensity distribution gradually broadened in reciprocal space upon cooling. Based on these observations, we propose a possible microscopic origin of the low-temperature metamagnetic transition in terms of a ferromagnetic instability enhanced by gradual localization of the itinerant Co-3d electrons. These results suggest that LuInCo4 provides a model system for investigating the interplay between electron localization and itinerant-electron ferromagnetism in cobalt-based metallic pyrochlore compounds.

Explore related subjects

cond-mat.str-el

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Taiki Shiotani, Subaru Yoshimoto, Yoshikazu Tabata, Yusuke Nambu, Katsuki Kinjo, Kazuhiro Nawa, Taku J. Sato, Takeshi Waki, Hiroyuki Nakamura. 2026-10-06. Gradual Localization of Itinerant Cobalt 3d Electrons in the Pyrochlore Ferromagnetic Metal LuInCo4. https://arxiv.org/abs/2610.08266

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Charge order through crystallization of Frenkel excitons: realization in kagome metals

Charge order is a widely observed and representative example of spontaneous broken symmetries in quantum states of matter. Owing to the large intra-atomic Coulomb energy, the charge redistribution in such an order typically implies significant alteration of the electronic and lattice properties of materials. While the standard description of charge order, namely a "charge density wave" instability of the Fermi surface, has been broadly and successfully applied to good metals, its applicability to correlated ionic materials has been rather limited. Here, we propose an alternative general scenario of charge order - crystallization of long-lived Frenkel excitons - suitable for these ionic materials. We demonstrate this scenario on the recently discovered kagome superconductors and successfully reproduce all the characteristics of experimental observations on both local charge correlations and long-range ordering. The proposed generic scenario offers a long-sought understanding of charge order applicable to modern correlated functional materials.

cond-mat.str-el↗

arXiv2026

Spiral states, first-order transitions and specific heat multipeak phenomenon in $J_1$-$J_2$-$J_3$ Ising model: A Wang-Landau algorithm study

The classical $J_1$-$J_2$-$J_3$ Ising model on the honeycomb lattice is important for understanding frustrated magnetic phenomena in materials such as FePS$_3$ and Ba$_2$CoTeO$_6$, where diverse phases (e.g., striped, zigzag, armchair) and magnetization plateaus have been experimentally observed. To explain the experimental results, previous mean-field studies have explored its thermal phase transitions, identifying armchair phases and striped phases, but their limitations call for more reliable numerical investigations. In this work, we systematically revisit the classical $J_1$--$J_2$--$J_3$ Ising model using the Wang--Landau algorithm; in strongly frustrated parameter regimes where the Wang--Landau sampling becomes difficult, we further employ parallel tempering and a two-replica cluster algorithm combined with population annealing. We find that the armchair (AC) phase, previously reported in mean-field and experimental studies, actually coexists with the spiral (SP) phase, with their combined degeneracy reaching 20-fold (4-fold for the AC states and 16-fold for the spiral states). The phase transitions and critical exponents are studied at different interaction values. We observe first-order phase transitions, continuous phase transitions, and even the multipeak phenomenon in frustrated systems. These results clarify the nature of phases and phase transitions in frustrated Ising systems and their exponents, and additionally provide inspiration for experimental efforts to search for the spiral state and the specific-heat multipeak phenomenon.

cond-mat.str-el↗

arXiv2026

The flow of local quantum fluids: Conservation laws and vertex corrections from many-body linear-response theory with local self-energy

In non-diffusive conduction regimes of strongly correlated quantum electron systems, electromagnetic perturbations simultaneously probe the electronic dynamics in time and space: the exchanged energy $\hbar ω$ excites retarded, i.e., frequency-dependent, many-body interactions, while the probing spatial modulation renders the response spatially nonlocal, i.e., dependent on the external wave vector $\vec{q}$. This work derives the nonlocal electrodynamic response of such dynamical quantum fluids assuming local but frequency-dependent self-energies and particle-hole irreducible two-particle vertex functions, and preserving charge/mass conservation. The latter is ensured by Bethe-Salpeter equations for renormalized interaction vertices, entering the Kubo formalism for two-particle correlation functions (e.g., for density, currents, momentum, stress). Within such a framework, exact symmetry criteria for the absence of vertex corrections are inferred. In particular, vertex corrections vanish at $q=0$ for single-particle dispersions that are even and bare interaction vertices that are odd with respect to specific momentum-space point group transformations, including inversion for vector vertices, and mirror reflections or two- or higher-fold rotations for tensor vertices. If the dispersion is isotropic, vertex corrections vanish from the transverse part ($\perp\vec{q}$) of vectorial vertices (such as for electric/particle current) at any finite $\hbar ω$ and $\vec{q}$. These cancellations extend to the full current-current correlation function for quadratic isotropic dispersion. Further symmetry breaking, multiband effects, and the additional imposition of momentum conservation, are discussed, with application to the Hall viscosity of Landau levels. Explicit expressions for generic nonlocal correlation functions are derived for Fermi liquids and non-Fermi liquids.

cond-mat.str-el↗