New aspects in topological heavy fermion systems

Heavy fermion materials provide a playground to extend our current understanding of topological phases of matter. This talk will present two new types of topological Kondo systems that go beyond the standard models. Firstly, when topology meets nonsymmorphic crystal symmetries, a Z4 topological insulating phase emerges with Mobius twisted surface states. The heavy fermion semimetal CeNiSn is one candidate ”Mobius Kondo Insulators”[1]. Secondly, heavy Weyl semimetals can emerge from topological Kondo insulators drive by the formation of a parity-violating hybridization between d- and f-electrons [2]. We show the renormalization effect induced by hybridization and the development of the surface Kondo breakdown, which gives rise to a temperature-dependent of re-configuration of Fermi arcs which will be visible in quantum oscillation experiments.

[1] P.-Y. Chang, O. Erten, and P. Coleman, "Mobius Kondo Insulators" Nature Physics 13, 794-798 (2017).
[2] O. Erten, P.-Y. Chang, P. Coleman, and A. Tsvelik, "Skyrme insulators: insulators at the brink of superconductivity", Phys. Rev. Lett. 119, 057603 (2017).