Berlin 2018 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 11: Topological insulators II (joint session HL/TT)

HL 11.8: Talk

Monday, March 12, 2018, 17:00–17:15, A 151

Topological design applied to the control of acoustic phonons — •Martin Esmann, Omar Ortiz, Fabrice R. Lamberti, Pascale Senellart, Aristide Lemaitre, and Daniel Lanzillotti-Kimura — CNRS Centre de Nanosciences et de Nanotechnologies (C2N), 91460 Marcoussis, France

The control and manipulation of acoustic phonons in the GHz-THz range appears as a new resource in the engineering of nanodevices. Here, we introduce the use of spatial mode symmetries of Bloch modes in a semiconductor superlattice to confine and control the propagation of phonons. We generate confined topological modes that are described by topological invariants and a topological transition upon band gap inversion [1]. This topological interface state between two finite size superlattices of different topology is a concept readily extendable to 3D in micropillars [2,3].

We experimentally evidence such a topologically confined nanophononic interface state in a planar structure both by coherent phonon generation (pump-probe) measurements and high resolution Raman scattering spectroscopy. Nanophononic topological interface states like the ones presented here could be at the base of developing single phonon sources, phononic sensors and phonon lasers, whose optical counterparts all led to key advances in applied photonics.

[1] M. Xiao et al., Phys. Rev. X 4, 021017 (2014).

[2] F. R. Lamberti et al., Opt. Express 25, 24437-24447 (2017).

[3] M. Esmann et al., submitted (2017).