講演題目: Na Cobaltates: from materials to correlations and topology
講師: Henri Alloul 氏 (Laboratoire de Physique des Solides, Universite Paris-Saclay)
日時: 2022年6月2日（木） 16:30-18:00
場所: 北海道大学 理学部 2-211室
要旨:
Electronic topology in metallic kagome compounds is under intense scrutiny. I shall present transport experiments in the specific Na cobaltate phase Na2/3CoO2 in which NMR data have revealed that the ordering of the Na differentiates a Co kagome sub-lattice in the triangular CoO2 layers. Hall and magneto-resistance (MR) data under high fields give evidence for the coexistence of light and heavy carriers. At low temperatures, the dominant zero field conductivity is due to light electronic carriers. Its suppression by a B-linear MR, suggests Dirac like quasiparticles. Lifshitz transitions induced at large B and Tunveil the lower mobility carriers. They display a negative B2 MR due to scattering from magnetic moments likely pertaining to a flat band. We underline an analogy with heavy Fermion physics.
世話人：井原慶彦
（北海道大学大学院理学研究院物理学部門）