Momentum-space topology and quantum geometry of graphite

CFM Seminars

Speaker

Prof. Tero Heikkilä
University of Jyväskylä, Finland

When

2025/10/20
15:00

Place

CFM Auditorium

Host

CFM Colloquium Series Committee

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CFM COLLOQUIUM SERIES

Prof. Tero Heikkilä will describe how different types of graphite are nodal line semimetals with intriguing topological properties. The most stable AB or Bernal graphite has two sets of four nodal lines, around each valley, and the metastable ABC or rhombohedral graphite has two spiral nodal lines, one in each valley. These structures are quite straightforward to understand by starting from the individual graphene layer spectra containing the nodal (Dirac) points that are also topologically protected. He will describe the two characteristic observable features of topological media, namely the bulk-boundary correspondence and the (quantized) anomalous responses for these systems. If time allows, he will also show how ABC graphite surface states feature almost "ideal" quantum geometry in the sense that the quantum geometry properties of those states resemble those of Landau levels. This has interesting consequences for interaction effects on those surfaces.