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HL: Fachverband Halbleiterphysik
HL 40: Thermal, acoustic and transport properties
HL 40.8: Vortrag
Mittwoch, 18. März 2020, 11:45–12:00, POT 151
Topological nanomechanical states by band inversion — •Martin Esmann1, Fabrice R. Lamberti1, Guillermo Arregui2, Omar Ortiz1, Carmen Gomez-Carbonell1, Pascale Senellart1, Clivia Sotomayor-Torres2, Pedro David Garcia2, Aristide Lemaitre1, and Daniel Lanzillotti-Kimura1 — 1CNRS, Centre for Nanoscience and Nanotechnology (C2N), Palaiseau, France — 2Catalan Institute of Nanoscience and Nanotechnology (ICN2), Barcelona, Spain
Many concepts studied in nanomechanics to control the confinement and propagation of acoustic phonons were inspired by their counterparts in optics and electronics. In these fields, the consideration of topological invariants has had a great impact for the generation of robust confined states. Here, we introduce this concept of topological invariants to nanophononics [1,2] and experimentally implement a GaAlAs heterostructure supporting a robust topological interface state at 350 GHz. The state is constructed through band inversion[3], by concatenating two semiconductor superlattices with inverted spatial mode symmetries. We experimentally evidenced the mode through Brillouin spectroscopy [1] and study its dynamics by picosecond optical pump-probe spectroscopy [3]. The reported robust topological interface state could become part of nanophononic devices requiring robust resonances such as mass sensors or phonon lasers.
[1] M. Esmann et al., PRB 97, 155422 (2018). [2] M. Esmann et al. PRB 98, 161109(R) (2018). [3] M. Xiao et al., Phys. Rev. X 4, 021017 (2014). [4] G. Arregui et al. APL Photonics 4, 030805 (2019).