The intricate interplay between spin and lattice degrees of freedom in two-dimensional magnetic materials plays a pivotal role in modifying their magnetic characteristics, engendering hybrid quasiparticles, and implementing functional devices. Herein, we present our comprehensive and in-depth investigations on magnetic and lattice excitations of MnPSe3-xSx (x = 0, 0.5, and 1.5) alloys, utilizing temperature- and polarization-dependent Raman scattering. Our experimental results reveal the occurrence of multiple phase transitions, evidenced by notable changes in phonon self-energy and the appearance or splitting of phonon modes. These emergent phases are tied to the development of long and short-range spin-spin correlations, as well as to spin reorientations or magnetic instabilities. Our analysis of two-magnon excitations as a function of temperature and composition showcases their hybridization with phonons whose degree weakens with increasing x. Moreover, the suppression of spin-dependent phonon intensity in chemically most-disordered MnPSe3-xSx (x = 1.5) suggests that chalcogen substitution offers a control knob of tuning spin and phonon dynamics by modulating concurrently superexchange pathways and a degree of trigonal distortions.
@article{arxiv.2404.11099,
title = {Interplay between magnetic and lattice excitations and emergent multiple phase transitions in MnPSe3-xSx},
author = {Deepu Kumar and Nguyen The Hoang and Yumin Sim and Youngsu Choi and Kalaivanan Raju and Rajesh Kumar Ulaganathan and Raman Sankar and Maeng-Je Seong and Kwang-Yong Choi},
journal= {arXiv preprint arXiv:2404.11099},
year = {2024}
}