Mismatch between Raman shear modes and ferroelectric polarization in 3R-MoS2
Abstract
Sliding ferroelectricity in parallel-stacked two-dimensional van der Waals materials enables a broad range of novel device concepts, but exploiting it requires reliable, non-destructive assignment of the underlying stacking order and polarization state. Here, we combine Kelvin-probe force microscopy (KPFM) with low-frequency Raman spectroscopy to probe the polarization domains and stacking configurations of a exfoliated trilayer 3R-MoS2 flake on a hBN substrate. We find that ABA and BAB - both stackings with zero net polarization - are indistinguishable in KPFM, yet show drastically different low-frequency shear modes. This observation is reproduced across multiple flakes and is corroborated by low-temperature photoluminescence. Notably, the standard bond-polarizability model does not account for the difference in shear-mode activity between the ABA and BAB configurations, indicating that the interlayer Raman response of these stackings is governed by physics beyond a simple polarizability picture. Our results show that none of the here-used individual techniques alone is sufficient to assign sliding-ferroelectric stacking order and motivate a combined spectroscopic-scanning-probe approach.
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BibTeX
@misc{schwandtkrause2026mismatch,
title = {{Mismatch between Raman shear modes and ferroelectric polarization in 3R-MoS$_2$}},
author = {Johannes Schwandt-Krause and Jan-Niklas Heidkamp and Mohammed El Amine Miloudi and Swarup Deb and Elisabeth Grune and Kenji Watanabe and Takashi Taniguchi and Rico Schwartz and Oliver Kühn and Tobias Korn},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2608.11988},
eprint = {2608.11988},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.11988},
}
RIS
TY - UNPB
TI - Mismatch between Raman shear modes and ferroelectric polarization in 3R-MoS_2
AU - Johannes Schwandt-Krause
AU - Jan-Niklas Heidkamp
AU - Mohammed El Amine Miloudi
AU - Swarup Deb
AU - Elisabeth Grune
AU - Kenji Watanabe
AU - Takashi Taniguchi
AU - Rico Schwartz
AU - Oliver Kühn
AU - Tobias Korn
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2608.11988
UR - https://arxiv.org/abs/2608.11988
AB - Sliding ferroelectricity in parallel-stacked two-dimensional van der Waals materials enables a broad range of novel device concepts, but exploiting it requires reliable, non-destructive assignment of the underlying stacking order and polarization state. Here, we combine Kelvin-probe force microscopy (KPFM) with low-frequency Raman spectroscopy to probe the polarization domains and stacking configurations of a exfoliated trilayer 3R-MoS_2 flake on a hBN substrate. We find that ABA and BAB - both stackings with zero net polarization - are indistinguishable in KPFM, yet show drastically different low-frequency shear modes. This observation is reproduced across multiple flakes and is corroborated by low-temperature photoluminescence. Notably, the standard bond-polarizability model does not account for the difference in shear-mode activity between the ABA and BAB configurations, indicating that the interlayer Raman response of these stackings is governed by physics beyond a simple polarizability picture. Our results show that none of the here-used individual techniques alone is sufficient to assign sliding-ferroelectric stacking order and motivate a combined spectroscopic-scanning-probe approach.
ER -