Berry curvature and topological characterization for strongly correlated electron systems

Characterizing the topological nature of electronic states in strongly correlated quantum materials,

especially in cases with nodal excitations, is a problem of extensive current interest [1,2]. In non-

interacting cases, Bloch functions specify the Berry curvature and quantized topological charge of

symmetry protected band crossings. However, in strongly correlated systems, in particular where the

quasiparticle picture fails, Bloch functions cannot be used and no suitable alternative approaches are

available. Here we fill this void by developing a Green’s function approach. We illustrate our

approach in the extreme correlation limit with nodal states. Our formalism offers a way to

systematically characterize electronic topology in strongly correlated settings [3].

[1] Hu, H., Chen, L., Setty, C. Garcia-Diez, M., Grefe, S.E., Prokofiev, A., Kirchner, S., Vergniory,

M.G., Paschen, S., Cano, J. and Si, Q., 2021. arXiv preprint arXiv:2110.06182.

[2] Setty, C., Sur, S., Chen, L., Xie, F., Hu, H., Paschen, S., Cano, J. and Si, Q., 2023. arXiv preprint

arXiv:2301.13870.

[3] Setty, C et al (in prep)