# Dresden 2014 – wissenschaftliches Programm

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# HL: Fachverband Halbleiterphysik

## HL 101: Theoretical advances in interacting topological phases (organized by TT)

### HL 101.4: Topical Talk

### Donnerstag, 3. April 2014, 16:45–17:15, HSZ 03

**Topological Kondo Insulators: An Example of Correlated Quantum Spin Hall States** — •Fakher Assaad — Universität Würzburg

In the very same way as the heavy fermion paramagnetic state at *T*=0 is adiabatically
linked to a gas of free electrons, the topological Kondo insulator can be deformed to a quantum spin Hall
insulator without going through a quantum phase transition.
The interest however lies in the fact the quasi-particles forming this coherence state are dynamically created by
correlation effects, and may be viewed as the Kondo screening clouds of the magnetic impurities.
The minimal model to capture this piece of physics consists of odd parity localized f-states hybridizing
with an even parity conduction band alongside strong spin-orbit coupling and time reversal symmetry. In this talk
we will consider such a minimal model, and concentrate on the temperature dependence of various quantities from
the mixed valence to local moment regimes [1-2] The quantities we consider include topological invariants as well as the single particle spectral function on slab topologies. We show that there is a single low energy scale, the coherence scale, below which one observes the emergence of the topological state.

This work has been carried out in collaboration with J. Werner.

J. Werner and F. F. Assaad, Phys. Rev. B 88, 035113 (2013).

J. Werner and F. F. Assaad, arXiv:1311.3668.