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arXiv · 2309.02419

Phononic drumhead surface state in distorted kagome compound RhPb

Andrzej Ptok·William R. Meier·Aksel Kobiałka·Surajit Basak·Małgorzata Sternik·Jan Łażewski·Paweł T. Jochym·Michael A. McGuire·Brian C. Sales·Hu Miao·Przemysław Piekarz·Andrzej M. Oleś
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Abstract

RhPb was initially recognized as one of a CoSn-like compounds with $P6/mmm$ symmetry, containing an ideal kagome lattice of $d$-block atoms. However, theoretical calculations predict the realization of the phonon soft mode which leads to the kagome lattice distortion and stabilization of the structure with $P\bar{6}2m$ symmetry [A. Ptok et al., Phys. Rev. B 104, 054305 (2021)]. Here, we present the single crystal x-ray diffraction results supporting this prediction. Furthermore, we discuss the main dynamical properties of RhPb with $P\bar{6}2m$ symmetry. The bulk phononic dispersion curves contain several flattened bands, Dirac nodal lines, and triple degenerate Dirac points. As a consequence, the phononic drumhead surface state is realized for the (100) surface, terminated by the zigzag-like edge of Pb honeycomb sublattice.

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Andrzej Ptok, William R. Meier, Aksel Kobiałka, Surajit Basak, Małgorzata Sternik, Jan Łażewski, Paweł T. Jochym, Michael A. McGuire, Brian C. Sales, Hu Miao, Przemysław Piekarz, Andrzej M. Oleś. 2023-09-05. Phononic drumhead surface state in distorted kagome compound RhPb. https://doi.org/10.1103/physrevresearch.5.043231

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