Role of Gd 5d-Au 5d hybridization for the magnetic properties of Au-Al-Gd quasicrystal approximants

Goro Nozue; Hidenori Fujiwara; Satoru Hamamoto; Yuto Torii; Mai Sakaguchi; Sho Nakajima; Takuya D. Nakamura; Nonoka U. Sakamoto; Takayuki Kiss; Masaki Oura; Akira Yasui; Kotaro Higashi; Naomi Kawamura; Kojiro Mimura; Arata Tanaka; Asuka Ishikawa; Farid Labib; Shintaro Suzuki; Takafumi D. Yamamoto; Ryuji Tamura; Akira Sekiyama

arXiv · 2610.19727

Role of Gd 5d-Au 5d hybridization for the magnetic properties of Au-Al-Gd quasicrystal approximants

View original source ↗Read source document ↗Export metadata ↓

Abstract

We have studied the electronic states of magnetic Au-Al-Gd quasicrystal approximants, which exhibit different magnetic ground states at low temperatures, by orbital-selective soft and hard x-ray electron spectroscopies in the paramagnetic phase. Our results reveal that the valence electronic states vary among the Au-Al-Gd approximants with different magnetic ground states, whereas the Gd 4f electrons are localized in all of them. In particular, we find that the Gd 5d states are hybridized with the Au 5d states around the Fermi level, providing information about a local pathway for the intersite exchange interaction between the localized Gd 4f electrons. This hybridization strength varies among these samples. Our findings bring an orbital-resolved microscopic picture to the magnetism of rare-earth-based quasicrystals and approximants.

Explore related subjects

cond-mat.str-el

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Goro Nozue, Hidenori Fujiwara, Satoru Hamamoto, Yuto Torii, Mai Sakaguchi, Sho Nakajima, Takuya D. Nakamura, Nonoka U. Sakamoto, Takayuki Kiss, Masaki Oura, Akira Yasui, Kotaro Higashi, Naomi Kawamura, Kojiro Mimura, Arata Tanaka, Asuka Ishikawa, Farid Labib, Shintaro Suzuki, Takafumi D. Yamamoto, Ryuji Tamura, Akira Sekiyama. 2026-10-14. Role of Gd 5d-Au 5d hybridization for the magnetic properties of Au-Al-Gd quasicrystal approximants. https://arxiv.org/abs/2610.19727

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

KEEP EXPLORING

Related papers

arXiv2026

Magneto-optical signatures of plateau states in the kagome spin-ice HoAgGe

Coupling of itinerant electrons to non-collinear spin structures in frustrated rare-earth magnets leads to unusual transport properties. While these complex magnetic orders are expected to modify the electronic structure, underlying microscopic mechanisms have been rarely identified. Using magnetoreflectance spectroscopy and \textit{ab initio} calculations, we reveal reconstructions of the electronic structure across the magnetization plateaus of the kagome spin-ice HoAgGe. We find an unusual optical anisotropy: a larger conductivity perpendicular to the kagome planes originating from the hybridization of Ho $4f$ flat bands with conduction electrons. Moreover, these flat bands are also responsible for the pronounced magnetoreflectance observed at the metamagnetic transitions. Most importantly, the magnetoreflectance behaves completely differently for excitations near the Fermi level and higher-energy interband transitions. The former, expected to sensitively probe variations in band topology near the Fermi level, shows abrupt non-monotonous changes between the magnetic states, while the interband excitations mimic the field dependence of the magnetization. These observations imply that in HoAgGe, the unusual magnetotransport likely reflects variation of band topology between plateau states. More generally, our study shows that heavy-electron bands near the Fermi level offer an efficient way to control the band structure and thereby the transport and optical properties of non-collinear magnets.

cond-mat.str-el↗

arXiv2026

The thermopower properties of interacting systems

The Seebeck coefficient quantifies the voltage generated across a material in response to a temperature gradient. Recent studies have shown that strong electronic correlations can enhance this coefficient, producing anomalous behavior near half-filling associated with the Mott plateau. This raises the possibility that other interaction scales, not necessarily originating in Mott physics, could give rise to similar enhancements. Here, we investigate the Seebeck coefficient in the presence of attractive interactions, nearest-neighbor interactions, sublattice potentials, and electron-phonon coupling. The Seebeck coefficient is obtained via the Kelvin formula, using entropy data derived from density calculations within determinant quantum Monte Carlo (DQMC). We find that these additional interaction scales can indeed enhance the Seebeck coefficient and further induce multiple sign changes as a function of doping. We show that this anomalous behavior is associated with the opening of a gap in the ground state, as computed via cluster perturbation theory (CPT). Moreover, electron-phonon coupling alone-even in the absence of on-site repulsion-can produce a Seebeck anomaly. We relate these sign changes to a restructuring of the Fermi surface and an accompanying change in its topology, an effect commonly observed in cuprates.

cond-mat.str-el↗

arXiv2026

Static spin exchange-correlation kernel of the uniform electron gas at finite temperature

We determine the temperature and momentum dependence of the static spin exchange--correlation kernel of the unpolarized three-dimensional uniform electron gas using variational diagrammatic Monte Carlo. The calculations cover metallic densities with Wigner--Seitz radii $r_s=1\!-\!4$ and temperatures $T/T_F=1/16\!-\!8$, where $T_F$ is the Fermi temperature. At low temperature, the calculated kernel approaches established ground-state parametrizations. Heating suppresses its Fermi-scale minimum and reduces its magnitude, while the relative momentum dependence evolves nonmonotonically through the warm-dense crossover. At the two highest temperatures studied, the spin kernel is nearly constant over $q \leq 2k_F$, where $k_F$ is the Fermi wave number. The charge kernel at $r_s=1$ retains pronounced momentum dependence under the same conditions, making a local approximation to the XC kernel more accurate in the spin channel over this interval. The directly sampled uniform response determines the XC free-energy curvature with respect to spin polarization, independently of a fitted polarization dependence. This curvature sets the interaction contribution to the free-energy cost of weak polarization and differs by several percent from the Groth--Dornheim--Bonitz parametrization at elevated temperatures. These results provide momentum-resolved reference data for finite-temperature spin-response theories and direct constraints on the spin dependence of thermal free-energy functionals.

cond-mat.str-el↗