Berlin 2024 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 57: Topology: Poster

TT 57.20: Poster

Wednesday, March 20, 2024, 15:00–18:00, Poster E

Phonon topology and winding of spectral weight in graphite — •Stanislav E. Nikitin¹, N. D. Andriushin², A. S. Sukhanov², A. N. Korshunov³, M. S. Pavlovskii⁴, and M. C. Rahn² — ¹Paul Scherrer Institut, Switzerland — ²TU Dresden, Germany — ³ESRF, France — ⁴Krasnoyarsk

The topology of electronic and phonon band structures of graphene is well studied and known to exhibit a Dirac cone at the K point of the Brillouin zone. In the talk I will discuss our recent results on phonon topology in graphite, the 3D analogue of graphene. We found a pair of modes that exhibit a weak anticrossing at the K point and can be viewed as a Dirac cone approximant. The spectral weight exhibit harmonic modulation above and below the Dirac energy in agreement with predictions for the Dirac point. We illustrate how such intensity modulation can be understood in terms of atomic displacements. Our results demonstrate how inelastic x-ray scattering can be used to experimentally investigate topological properties of the phonon band structure.

Keywords: Phonons; Topology; Inelastic x-ray scattering; Graphite