Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 72: Poster Session: Correlated Electrons
TT 72.6: Poster
Mittwoch, 14. März 2018, 15:00–19:00, Poster B
3D topological Kondo insulators: effects of strong correlations onthe stability of topological phases — •Paul Züge1, Soroush Arabi1, Francisco Meirinhos1, and Johann Kroha1, 2 — 1Physikalisches Institut and Bethe Center for TheoreticalPhysics, Universität Bonn, Germany — 2Center for Correlated Matter, Zhejiang University, Hangzhou, China
Topological Kondo insulators (TKI) are heavy-fermion (HF) materials where strong correlations generate a HF band with a hybridization gap around the Fermi level and the strong spin-orbit coupling in the 4f orbitals on the rare-earth sites, hybridizing with the light conduction electron band, induces non-trivial topology with conserved topological invariants in these bands. Since in all relevant energy scales, the HF band width, the gap and quasiparticle decay rates are of comparable size, the Kondo temperature TK, TKIs are ideal systems to study the stability of topological phases in the presence of interactions. However, most theoretical studies have been on the effective single-particle (mean-field) level up to now. We use the slave boson (SB) representation for the HF band and systematically expand around the SBMF saddle point, taking the Gaussian fluctuations of the SB field into account. Feeding the resulting self-energies back into the boson and fermion propagators, this leads to self-consistent saddle-point equations, which imply a finite spectral width for the HF states. We solve these equations self-consistently for the bulk of three-dimensional TKIs. We compute the HF and conduction electron spectral functions and analyse the stability of the topological hybridization gap.