Phonon Anharmonicity and Spin-Phonon Coupling in CrI3

Luca Tomarchio; Lorenzo Mosesso; Salvatore Macis; Loi T Nguyen; Antonio Grilli; Martina Romani; Mariangela Cestelli Guidi; Robert J Cava; Stefano Lupi

doi:10.3390/ma16144909

Phonon Anharmonicity and Spin-Phonon Coupling in CrI₃

Materials (Basel). 2023 Jul 9;16(14):4909. doi: 10.3390/ma16144909.

Authors

Luca Tomarchio^{1

2}, Lorenzo Mosesso^{1

2}, Salvatore Macis^{1

3}, Loi T Nguyen⁴, Antonio Grilli³, Martina Romani³, Mariangela Cestelli Guidi³, Robert J Cava⁴, Stefano Lupi^{1

2}

Affiliations

¹ Department of Physics, Sapienza University, Piazzale Aldo Moro 5, 00185 Rome, Italy.
² INFN Section of Rome, P.Le Aldo Moro, 2, 00185 Rome, Italy.
³ INFN-Laboratori Nazionali di Frascati, Via Enrico Fermi 54, 00044 Rome, Italy.
⁴ Department of Chemistry, Princeton University, Princeton, NJ 08544, USA.

Abstract

We report on the far-infrared, temperature-dependent optical properties of a CrI3 transition metal halide single crystal, a van der Waals ferromagnet (FM) with a Curie temperature of 61 K. In addition to the expected phonon modes determined by the crystalline symmetry, the optical reflectance and transmittance spectra of CrI3 single crystals show many other excitations as a function of temperature as a consequence of the combination of a strong lattice anharmonicity and spin-phonon coupling. This complex vibrational spectrum highlights the presence of entangled interactions among the different degrees of freedom in CrI3.

Keywords: optical spectroscopy; phonon anharmonicity; spin–phonon coupling; van der Waals ferromagnet.

Abstract

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