HiSOR x WPI-SKCM2ジョイントセミナー
Mapping the Rich Electronic Landscape of Distorted Kagome Metals
日時 2026年1月29日 （木） 13:30 - 14:30
場所 WPI-SKCM2研究棟（VBL） 2階 セミナー室（VBL204）
講師 Anup Pradhan Sakhya
(Research Institute for Synchrotron Radiation Science, Hiroshima University)
Quantum materials featuring a kagome lattice, in which corner-sharing triangles form a hexagonal framework, provide a unique platform to explore the interplay between lattice geometry, electron correlations, and spin interactions, and have attracted considerable attention in recent years [1]. In this talk, I will introduce LnTi3Bi4 (Ln = lanthanide), a novel family of distorted kagome metals that has drawn interest due to the combination of highly anisotropic magnetism and a rich electronic structure [2]. I will present a comparative ARPES and DFT study of several members of this series, highlighting their diverse yet interconnected electronic phenomena. In YbTi3Bi4, NdTi3Bi4, and LaTi3Bi4, we directly observe multiple van Hove singularities near the Fermi level, linearly dispersing Dirac-like states, and flat bands arising from destructive interference within the Ti-based kagome network [3-5]. These features are accompanied by strong electronic anisotropy, reflecting the broken sixfold rotational symmetry inherent to the distorted kagome lattice. I will also briefly discuss CeTi3Bi4, where the Ti kagome electronic structure couples to localized Ce3+ moments, giving rise to a rich magnetic phase diagram including a spin-density-wave ground state [6]. Together, these results establish LnTi3Bi4 as a versatile model system in which flat-band physics, Dirac topology, Fermi-surface instabilities, and magnetism can be systematically explored within a single materials family.
[1] Y. Wang et al., Nat Rev Phys 5, 635–658 (2023).
[2] B. R. Ortiz et al., Chem. Mater. 35, 9756 (2023).
[3] A. P. Sakhya et al., Commun. Mater. 5, 241 (2024).
[4] M. I. Mondal*, A. P. Sakhya* et al., Phys. Rev. B 112, L121104 (2025).
[5] A. P. Sakhya et al., Phys. Rev. Mater. 9, L111201 (2025).
[6] P. Park, B. R. Ortiz, M. Sprague, A. P. Sakhya et al., Nat Commun 16, 4384 (2025).
問合せ先 出田真一郎（放射光科学研究所）
