24–28 Jul 2023
MPI-FKF
Europe/Berlin timezone

Fundamental laws of chiral band crossings: local constraints, global constraints, and topological phase diagrams

24 Jul 2023, 16:45
2h 45m
2D5 (MPI-FKF)

2D5

MPI-FKF

Contributed Poster Poster Session

Speaker

Kirill Alpin (MPI FKF)

Description

We derive two fundamental laws of chiral band crossings: (i) a local constraint relating the Chern number to phase jumps of rotation eigenvalues; and (ii) a global constraint determining the number of chiral crossings on rotation axes. Together with the fermion doubling theorem, these laws describe all conditions that a network of chiral band crossing must satisfy. We apply the fundamental laws to prove the existence of enforced double Weyl points, nodal planes, and generic Weyl points, among others. In addition, we show that chiral space-group symmetries can not stabilize nodal lines with finite Chern numbers. Combining the local constraint with explicit low-energy models, we determine the generic topological phase diagrams of all multifold crossings. Remarkably, we find a four-fold crossing with Chern number 5, which exceeds the previously conceived maximum Chern number of 4. We identify materials crystallizing in space group 198, such as B20 materials and BaAsPt, as suitable compounds with this Chern number 5 crossing.

Primary authors

Andreas Leonhardt (Max Planck Institute for Solid State Research) Kirill Alpin (MPI FKF) Andreas Schnyder (Max Planck Institute for Solid State Research) Moritz Hirschmann (MSFK) Niclas Heinsdorf (Max Planck Institute for Solid State Research) Wan Yee Yau (Institute for Theoretical Physics III, University of Stuttgart) Xianxin Wu (Institute for Theoretical Physics, Chinese Academy of Sciences)

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