Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 90: Low-dimensional systems: Topological order (organized by TT)

HL 90.12: Talk

Thursday, April 3, 2014, 12:45–13:00, HSZ 204

Kondo holes in topological Kondo insulators — •Pier Paolo Baruselli and Matthias Vojta — Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany

The interplay between strong correlations and topology is a fast-developing and fascinating subject in the field of condensed matter.

Recently, the existence of topological Kondo insulators has been proposed [1]. In these materials the insulating behavior arises from strong correlations, that is from the Kondo screening of localized moments via conduction electrons, while non-trivial topology emerges from the structure of the hybridization between the local-moment and conduction bands.

We present a study of the physics of Kondo holes, i.e., missing local moments, in such topological Kondo insulators, using a self-consistent real-space mean-field theory. Kondo holes induce in-gap states which, for Kondo holes at or near the surface, hybridize with the topological surface state. In particular, we investigate the surface-state quasiparticle interference (QPI) induced by a dilute concentration of surface Kondo holes. We find that most QPI features can be interpreted by taking into account the shape of two-dimensional Fermi surface, together with the absence of backscattering characterizing Dirac cones in topological insulators. However, deviations from this simple picture arise: for example, the real part of the substrate Green’s function and of the scattering matrix cannot be neglected in several cases.
M. Dzero, K. Sun, V. Galitski, and P. Coleman, Phys. Rev. Lett. 104, 106408 (2010)