Observation of interplay between phonon chirality and electronic band topology

Felix G G Hernandez; Andrey Baydin; Swati Chaudhary; Fuyang Tay; Ikufumi Katayama; Jun Takeda; Hiroyuki Nojiri; Anderson K Okazaki; Paulo H O Rappl; Eduardo Abramof; Martin Rodriguez-Vega; Gregory A Fiete; Junichiro Kono

doi:10.1126/sciadv.adj4074

Observation of interplay between phonon chirality and electronic band topology

Sci Adv. 2023 Dec 15;9(50):eadj4074. doi: 10.1126/sciadv.adj4074. Epub 2023 Dec 15.

Authors

Felix G G Hernandez¹, Andrey Baydin^{2

3}, Swati Chaudhary^{4

5

6}, Fuyang Tay^{2

7}, Ikufumi Katayama⁸, Jun Takeda⁸, Hiroyuki Nojiri⁹, Anderson K Okazaki¹⁰, Paulo H O Rappl¹⁰, Eduardo Abramof¹⁰, Martin Rodriguez-Vega^{4

5}, Gregory A Fiete^{5

6}, Junichiro Kono^{2

3

11

12}

Affiliations

¹ Instituto de Física, Universidade de São Paulo, São Paulo, SP 05508-090, Brazil.
² Department of Electrical and Computer Engineering, Rice University, Houston, TX 77005, USA.
³ Smalley-Curl Institute, Rice University, Houston, TX 77005, USA.
⁴ Department of Physics, The University of Texas at Austin, Austin, TX 78712, USA.
⁵ Department of Physics, Northeastern University, Boston, MA 02115, USA.
⁶ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
⁷ Applied Physics Graduate Program, Smalley-Curl Institute, Rice University, Houston, TX 77005, USA.
⁸ Department of Physics, Graduate School of Engineering Science, Yokohama National University, Yokohama 240-8501, Japan.
⁹ Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
¹⁰ Instituto Nacional de Pesquisas Espaciais, São José dos Campos, SP 12201-970, Brazil.
¹¹ Department of Physics and Astronomy, Rice University, Houston, TX 77005, USA.
¹² Department of Materials Science and NanoEngineering, Rice University, Houston, TX 77005, USA.

Abstract

The recently demonstrated chiral modes of lattice motion carry angular momentum and therefore directly couple to magnetic fields. Notably, their magnetic moments are predicted to be strongly influenced by electronic contributions. Here, we have studied the magnetic response of transverse optical phonons in a set of Pb_1-xSn_xTe films, which is a topological crystalline insulator for x > 0.32 and has a ferroelectric transition at an x-dependent critical temperature. Polarization-dependent terahertz magnetospectroscopy measurements revealed Zeeman splittings and diamagnetic shifts, demonstrating a large phonon magnetic moment. Films in the topological phase exhibited phonon magnetic moment values that were larger than those in the topologically trivial samples by two orders of magnitude. Furthermore, the sign of the effective phonon g-factor was opposite in the two phases, a signature of the topological transition according to our model. These results strongly indicate the existence of interplay between the magnetic properties of chiral phonons and the topology of the electronic band structure.