Unraveling hidden Raman modes in α-MnTe: Effects of long-range dipole-dipole interactions on phonon bands
Abstract
In this study, we address the seemingly open question of disparity between the experimentally and theoretically observed Raman spectra for the altermagnetic α-MnTe. We establish that the consideration of long range (LR) dipole-dipole interaction is crucial to accurately estimate the phonon band structure and thereby capturing each of the experimentally observed Raman signatures. The LR correction brings about substantial changes to the high-frequency optical modes and their group-theoretical representations. Specifically, for the highly debated Raman peak around 175 cm−1, alongside the Raman silent B1u mode, the LR corrections introduce Raman-active longitudinal optical A′ and A1, and transverse optical A1 modes. Overall, the calculated Raman spectra suggest that the intensity of these modes is weak in the pristine system, while certain prescribed distortions can increase their intensity. The Raman peak around 140 cm−1, as observed experimentally, is identified to be emerging from a higher-order Raman process due to zone off-center contributions, while the other debated 120 cm−1 peak has both the zone center and off-center contributions.
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BibTeX
@misc{jana2026unraveling,
title = {{Unraveling hidden Raman modes in $α$-MnTe: Effects of long-range dipole-dipole interactions on phonon bands}},
author = {Susmita Jana and Rajib Sarkar and Dhavala Suri and B. R. K Nanda},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.08221},
eprint = {2610.08221},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.08221},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Unraveling hidden Raman modes in α-MnTe: Effects of long-range dipole-dipole interactions on phonon bands
AU - Susmita Jana
AU - Rajib Sarkar
AU - Dhavala Suri
AU - B. R. K Nanda
PY - 2026
DA - 2026/10/06
PB - arXiv
DO - 10.48550/arxiv.2610.08221
UR - https://arxiv.org/abs/2610.08221
AB - In this study, we address the seemingly open question of disparity between the experimentally and theoretically observed Raman spectra for the altermagnetic α-MnTe. We establish that the consideration of long range (LR) dipole-dipole interaction is crucial to accurately estimate the phonon band structure and thereby capturing each of the experimentally observed Raman signatures. The LR correction brings about substantial changes to the high-frequency optical modes and their group-theoretical representations. Specifically, for the highly debated Raman peak around 175 cm^−1, alongside the Raman silent B_1u mode, the LR corrections introduce Raman-active longitudinal optical A^′ and A_1, and transverse optical A_1 modes. Overall, the calculated Raman spectra suggest that the intensity of these modes is weak in the pristine system, while certain prescribed distortions can increase their intensity. The Raman peak around 140 cm^−1, as observed experimentally, is identified to be emerging from a higher-order Raman process due to zone off-center contributions, while the other debated 120 cm^−1 peak has both the zone center and off-center contributions.
ER -